A taxonomic revision of Zygodon (Orthotrichaceae) in southern South America

Graciela Calabrese

A taxonomic revision of Zygodon (Orthotrichaceae) in southern South America GRACIELA M. CALABRESE Real Jardı́n Botánico, Plaza de Murillo 2, E-28014 Madrid, Spain. e-mail: calabrese@rjb.csic.es ABSTRACT. The genus Zygodon Hook. & Taylor is revised for southern South America (Andean-Patagonian and Fuegian regions). Thirteen taxa (twelve species and one variety) are recognized as occurring in the region: Z. bartramioides Malta, Z. chilensis Calabrese & F. Lara, Z. hookeri Hampe var. hookeri, Z. hookeri var. leptobolax (Müll. Hal.) Calabrese comb. nov., Z. intermedius Bruch & Schimp., Z. jaffuelii Thér., Z. magellanicus Dusén ex Malta, Z. menziesii (Schwägr.) Arnott, Z. papillatus Mont., Z. pentastichus (Mont.) Müll. Hal., Z. pichinchensis (Taylor) Mitt., Z. reinwardtii (Hornsch.) Bruch & Schimp. and Z. obtusifolius Hook. All taxa previously considered to grow in southern South America were studied, and many were typified. Because of the biogeographical connections with other Southern Hemisphere landmasses, some taxa from other areas (e.g., Australasia or South Africa) were also considered. The studied taxa are a good representation of the genus as a whole, thus allowing one to conclude that Zygodon, worldwide, consists of three subgenera: subg. Zygodon, the species of which have papillose leaf cells that are flat as seen in crosssection, and that can be further divided in two sections, sect. Zygodon defined by leaf basal cells not in differentiated bands and seta distally dextrorse, and sect. Stenomitrium Mitt. with leaf basal cells disposed in differentiated alternating bands and seta distally sinistrorse; subg. Codonoblepharon (Schwägr.) Calabrese stat. nov. comprising species with smooth, flat leaf cells in cross-section; and subg. Obtusifolium (Malta) Calabrese stat. nov., including species with papillose, bulging leaf cells. For each of the accepted taxa, keys, descriptions, illustrations, a complete list of synonyms previously used in the study area (sometimes expanded with names from abroad), ecology, distribution maps, variability and differentiation from related taxa are provided. Study of the peristome of Zygodon with the SEM provides new data about its structure and ornamentation. KEYWORDS. Argentina, Chile, Orthotrichaceae, South America, taxonomy, Zygodon. ^ Zygodon Hook. & Taylor belongs to the Orthotrichaceae, a family that includes mosses with small, often papillose upper leaf cells, mitriform or cucullate calyptra, terminal perichaetia and sporophytes with arthrodontous and diplolepidous peristomes consisting of endostomial segments alternating with exo- ^ ^ stomial teeth (Goffinet 1998; Vitt 1982). The family includes four subfamilies according to Vitt (1972): Zygodontoideae (Schimp.) Broth., Orthotrichoideae (Schimp.) Broth., Drummondioideae Vitt and Macromitrioideae Broth. The subfamilies are defined by calyptrae shape, growth of main stem and position of THE BRYOLOGIST 109(4), pp. 453–509 Copyright Ó2006 by the American Bryological and Lichenological Society, Inc. 0007-2745/06/$5.85/0 454 the bryologist 109(4): 2006 perichaetia: Zygodontoideae and Orthotrichoideae include acrocarpous mosses while Drummondoideae and Macromitrioideae comprise cladocarpous mosses. In addition, the calyptra is cucullate in the Zygodontoideae and Drummondioideae, but mitriform in the Orthotrichoideae and Macromitrioideae. According to Vitt (1982), the Zygodontoideae includes Zygodon and Stenomitrium (Mitt.) Broth. Later, Goffinet and Vitt (1998) considered the Orthotrichaceae to consist of but two subfamilies, each with two tribes: subfamily Orthotrichoideae (Zygodonteae and Orthotricheae) and subfamily Macromitrioideae (Macromitrieae and Schlotheimieae). These authors presented the first molecular studies on the family to interpret its phylogeny. According to them, the Zygodonteae includes Codonoblepharon Schwägr., Bryomaltaea Goffinet, Leratia Broth., Zygodon, Leptodontiopsis Broth., Pleurorthotrichum Broth. and Stenomitrium (Mitt.) Broth., after segregating the traditional Zygodon in four genera: Zygodon, Stenomitrium, Codonoblepharon and Bryomaltaea. In the present treatment, I consider Zygodon s.l. to include acrocarpous mosses with cucullate, smooth, usually naked calyptrae, exserted capsules with longitudinal ribs and diplolepidous peristomes. The main gametophytic characters are the 6 isodiametric, thick-walled, papillose or smooth upper leaf cells, the costae with ventral guide cells and dorsal stereids, and the characteristic propagula developed in the leaf axils. Zygodon is distributed mainly in tropical and sub-tropical areas, with most species in America from Mexico to Tierra del Fuego, especially through the Andes. Brotherus (1902–1903) recognized 93 species worldwide (57 in the Americas, 14 in Africa, 13 in Australia, 10 in Asia and 8 in Europe) and later raised the number to 112 (Brotherus 1925). Malta (1926), in the only worldwide revision of the genus, recognized 77 species, whereas Index Muscorum (Wijk et al. 1969) reported 90 taxa, and more recently Vitt (1982) estimated 52 species worldwide. Currently, 91 species of Zygodon are recognized according to Crosby et al. (1999). After Malta’s monograph (1926), revisions of Zygodon have been published for Europe and Macaronesia (Düll 1985) and Australasia (Lewinsky 1990). It has also been treated in regional floras: Moss Flora of Mexico (Vitt 1994), Prodromus Bryologiae Novo-Granatensis (Churchill & Linares 1995), Flora of Southern Africa (Magill & Van Rooy 1998), Moss Flora of the Upper Bureya River (Russian Far East) (Ignatov et al. 2000) and Moss Flora of Central America (Allen 2002). However, southern South America, despite its richness in Zygodon, both in terms of taxa number and abundance (Greene 1986; He 1998; Kühnemann 1938; Matteri 1985, 2003; Matteri & Schiavone 2002; Seki 1974), lacks an updated revision, here undertaken. During the course of this revisionary study, one species was described as new from southern Chile (Calabrese et al. 2006) and ten were reduced to synonymy. Twelve species and one variety are recognized from the Andean-Patagonian and Fuegian regions: Zygodon bartramioides, Z. chilensis, Z. hookeri var. hookeri, Z. hookeri var. leptobolax, Z. intermedius, Z. jaffuelii, Z. magellanicus, Z. menziesii, Z. papillatus, Z. pentastichus, Z. pichinchensis, Z. reinwardtii and Z. obtusifolius. MATERIALS AND METHODS This revision is based on some 1300 herbarium specimens from BA, BCRU, BM, CHR, FH, G, H, HBG, HIRO, JE, MA, MO, NY, PC, PRE, S, TR-VENTURI, UBC, UC, the private herbaria of Celina M. Matteri (Buenos Aires) and the Laboratory of Bryology of the Universidad Autónoma de Madrid (Spain). I also conducted field work during the austral summers (December–March) for the period 1995–1998, and April 2001. Specimens collected by the author are in her personal herbarium with some duplicates in BCRU and MA. Specimens were studied either in water or mounted in Hoyer’s (Anderson 1954) or glyceringelatin (Johansen 1940). Illustrations of leaves, cells, propagula, capsules, peristomes and spores were made with a camera lucida on an Olympus BX40 light microscope. Digital microphotographs were taken with MOTICAM 1300 and Nikon HFX-II cameras. Peristomes were also studied under the SEM. Mature intact capsules had their opercula removed and were dry-mounted on aluminium stubs covered with adhesive, covered by gold and studied with a Philips XL30 scanning electron microscope with EDAX Dx4i analyser at 20 kV and a working distance of 10–14 mm. In this treatment, all measurements were made from wet material. Laminal width was measured at Calabrese: Zygodon in southern South America the broadest part of the leaf, costal width in the lower third, cell measurements include the walls, capsule length excludes the operculum, seta length includes the vaginula and plant length refers only to the gametophyte. The species have been distinguished on the basis of morphological characters. Descriptions of species include variability observed in all specimens examined, from the study area and from Australia, New Zealand, Tasmania, Africa and Central and South America. Terminology follows Magill (1990). The regional distribution maps are solely based on specimens studied by the author. In ‘‘Selected specimens examined’’ only one specimen per geographical unit is cited, and the total number of specimens is in parentheses at the head of the section. A complete list of specimens studied is available upon request. TAXONOMIC CHARACTERS For this study I analyzed and evaluated the taxonomic characters commonly used in Zygodon. I also searched for new, stable characters that could be of use in the taxonomy of the genus. Most Zygodon species are dioicous and sporophytes are uncommon. Thus, traditionally, attention has been mainly given to gametophytic traits. However, in this revision I have used both gametophytic and sporophytic traits as far as possible to define taxa. Gametophyte. Habit.—Zygodon plants are typically acrocarpic. Gametophytes are erect, 6 branched, forming loose (e.g., Z. magellanicus) or dense (e.g., Z. menziesii) turfs. The exception is the Andean Z. pentastichus which forms 6 loose mats with plagiotropic stems and erect branches to 5 cm high. Mitten (1869) and Brotherus (1902–1903) considered the plagiotropic habit of great taxonomic value and segregated Z. pentastichus in an independent section, Zygodon sect. Stenomitrium Mitt., or at the generic level as Stenomitrium (Mitt.) Broth. Size of plants is very variable. Low turfs less than 2 cm high are frequent, and the smallest plants of some species (e.g., Z. obtusifolius, Z. intermedius, Z. jaffuelii) reach only 0.2–0.5 cm. On the other hand, the Andean Z. pichinchensis is always over 4 cm, and can reach 11 cm tall. 455 Regarding robustness, specimens of some species are fairly robust (e.g., Z. pichinchensis), while others are slender (e.g., Z. papillatus). This character varies according to turf density and height, as it seems influenced by environmental conditions. However, it is useful to separate two closely related species, Z. magellanicus and Z. papillatus (Calabrese et al. 2002). The color of the upper parts of the plants varies from yellowish-green (e.g., Zygodon intermedius) to 6 dark olive-green (e.g., Z. obtusifolius), rarely reddishbrown (e.g., Z. pichinchensis). Rhizoids.—Rhizoids variably cover the stem as a tomentum, sometimes almost completely, as in Z. pichinchensis, Z. squarrosus (Taylor) Müll. Hal. and Z. nivalis Hampe, and occasionally are also developed at older leaf bases (Z. bartramioides and Z. pichinchensis). Color varies from yellowish-brown to reddish-brown; the only exception in the genus is Z. forsteri (With.) Mitt., with hyaline to almost white rhizoids. The rhizoids are usually smooth to slightly roughened, although sometimes they can be papillose, a character that separates two otherwise similar species: Z. magellanicus, with papillose rhizoids, and Z. papillatus, with smooth or rarely slightly roughened, never papillose, rhizoids (Calabrese et al. 2002). Stems.—Stems are 6 rounded to pentagonal, usually with large, uniform, thin-walled central cells surrounded by 1–3 layers of smaller, thick-walled cortical cells. This is the most common stem anatomy, and the only one seen in all the Andean-Patagonian and Fuegian taxa of Zygodon. However, Z. minutus Müll. Hal. & Hampe and Z. gracillimus Broth. ex M. Fleisch., two Australasian members of subg. Codonoblepharon (¼ sect. Bryoides Malta), have different stem anatomy (Lewinsky 1990): Z. minutus lacks differentiated cortical cells, while in Z. gracillimus all cells are thick-walled or a few in the center are thin-walled. Leaf arrangement.—In most Zygodon taxa, the leaves are spirally arranged, but in species with clearly pentagonal stems they show a 6 distinct pentastichous disposition, like in the Andean Z. campylophyllus Müll. Hal., Z. longicellularis D. G. Griffin, Z. pichinchensis, Z. quitensis Mitt., Z. venezuelensis D. G. Griffin and especially Z. pentastichus. Leaf orientation.—When dry, leaves are appressed to erect, straight and keeled in most Zygodon taxa, 456 the bryologist 109(4): 2006 although some species have patent, flexuose to twisted or rarely homomallous leaves. When moist, leaves vary from erect to squarrose-recurved, although spreading leaves are most typical. Zygodon pentastichus differs from any other species in the genus by its sheathing base and a patent distal part. Leaf size.—Most taxa of Zygodon have leaves 1–2 mm long. Exceptions are Z. erosus, Z. pentastichus, Z. runcinatus Müll. Hal. and Z. trichomitrius Hook. & Wilson, with leaves 2–4 mm long, and Z. obtusifolius and Z. papillatus with smaller leaves (usually , 1 mm). Leaf width is usually 0.2–0.6 mm. Leaf shape.—Lanceolate leaves with acute apex are typical in Zygodon, although three species in the study area deviate: Z. bartramioides with lanceolaterhomboidal leaves with clearly defined shoulders; Z. menziesii with 6 lingulate leaves; and Z. obtusifolius with lingulate leaves and a rounded-obtuse apex. The rounded-obtuse apex of Zygodon obtusifolius was traditionally considered diagnostic for subg. Obtusifolium (Malta) Calabrese (¼ sect. Obtusifolii Malta). However, the recently described Z. conoideus var. lingulatus S. R. Edwards (Edwards et al. 2000) also has rounded-obtuse leaf apices, but belongs to subg. Zygodon. Leaf margins.—Margins are usually plane, more rarely slightly recurved in medial and lower portions of leaves (e.g., Zygodon menziesii), or lower parts (e.g., Z. obtusifolius). When leaves are undulate, this is especially conspicuous at margins (e.g., Z. hookeri and Z. reinwardtii; Figs. 20C, 21C). Most species have margins entire and smooth toward the leaf base, and entire and papillose in the rest of the leaf. However, Z. obtusifolius has papillosecrenulate margins for almost their entire length, and leaf margins in Z. pichinchensis appear spinulose to spinose by the very long papillae. Species with smooth leaf cells (subg. Codonoblepharon) have entire and smooth margins throughout. Finally, some species (Z. hookeri var. hookeri, Z. reinwardtii and Z. runcinatus) have denticulate to dentate margins at the leaf apex. In Z. hookeri var. hookeri and Z. reinwardtii some totally entire leaves or specimens occasionally occur, and also some weak denticulations can be found in species with leaf margins usually entire, such as Z. hookeri var. leptobolax, Z. jaffuelii and Z. bartramioides. Although traditionally margin ornamentation has been considered of great taxonomic value, it shows wide infraspecific variation and must be used with care. Leaf costa.—The costa typically ends below the apex, and seldom reaches the apex or beyond. Ventrally it is always smooth, and dorsally can be smooth or papillose, spinose in Z. pichinchensis. In cross-section it has two ventral guide cells and a band of dorsal stereids (Zander & Vitt 1979), weakly differentiated only in Zygodon obtusifolius. Costa anatomy allows the discrimination of sterile material of other genera with similar habits. Thus, Leptodontium (Müll Hal.) Hampe ex Lindb. (Pottiaceae) and Amphidium Schimp. (Rhabdowesiaceae), that in the past were considered Orthotrichaceae because of their gametophytic similarity with Zygodon, have central guide cells and dorsal and ventral stereid bands. Leaf cross-section.—The leaf lamina in Zygodon is typically unistratose, except for the bistratose portions seen only seldom in the margins of Z. menziesii, and in the recently described Z. bistratus Calabrese & J. Muñoz, from the Iberian Peninsula, with bistratose lamina (Calabrese & Muñoz 2006). Distal laminal cells (Fig. 1).—Cells in the distal 2/3 of leaf are isodiametric (sub-quadrate, hexagonal or rounded) to oval, 6 thick-walled and usually 8–15 lm in the larger diameter, although the European Z. forsteri, with cells 15–27 lm, clearly deviates. Cell surfaces are flat in all species except in Z. obtusifolius, with distinctly bulging cells (Figs. 1E, 6F). Most Zygodon taxa have distal cells papillose, although the group of closely related species considered here as subg. Codonoblepharon, in which I include Z. forsteri (cf. Matcham & O’Shea 2005), have completely smooth cells. This is a rare characteristic in the Orthotrichaceae, where only Muelleriella Dusén, Stoneobryum D. H. Norris & H. Rob. and few unrelated Orthotrichum Hedw. species lack papillae. However, in Zygodon, all species with smooth leaf cells also share other propagular and sporophytic traits that support the taxonomic value of this character and the validity of subg. Codonoblepharon. Shape, size and number of papillae per cell are critical for species recognition. Most Zygodon species have simple papillae (Figs. 1B, D, 8D, 10G, 12E, 14D–E, 17D–E, 19D–E, 20E, 21E–F, 22E–F), with Z. bartramioides, Z. papillatus and Z. pichinchensis (Figs. Calabrese: Zygodon in southern South America 457 Figure 1. Cells in the middle portion of leaf. A. Zygodon papillatus (Gay s.n., PC-MONTAGNE). B. Z. magellanicus (Matteri & Schiavone CM 2449, S). C. Z. pichinchensis (Matteri et al. CM 6144, BA). D. Z. chilensis (Eyerdam 10999-a, UC). E. Z. obtusifolius, the arrow points to a forked papilla (Cleef 6062, G). F. Z. menziesii (Schwabe 81, S-B1887). Scale: 25 lm. 1A, 15D–E, 16H) also having branched ones intermingled. Finally, Z. obtusifolius has only fused or branched papillae (Figs. 1E, 6D, F). Papillae can be acute, sub-acute or blunt, usually less than 5 lm high, although in Z. pichinchensis they are over 10 lm (Fig. 1C). In Z. pentastichus, Z. chilensis and Z. bartramioides, the only southern South American members of sect. Stenomitrium, papillae are wider in diameter than any other species in the genus (Fig. 1D). Among the studied species, number of papillae per cell varies from one to three in Z. pichinchensis to six to nine in Z. hookeri var. leptobolax. Basal laminal cells (Fig. 2).—Cells in the basal 1/3 of leaf are usually strongly differentiated from distal cells: smooth or seldom with few papillae, subquadrate to rectangular, hyaline and commonly much longer. The exception is Z. obtusifolius, with smooth to weakly papillose basal cells, otherwise identical to distal ones. In contrast, Z. bartramioides and Z. pentastichus have a strong and sudden differentiation between upper and basal cells. The other species show a 6 gradual transition, although basal cells have a net morphologic differentiation. The almost undifferentiation of basal cells in Z. obtusifolius has been considered as a primitive character (Goffinet et al. 1998) and should be of taxonomic importance. Basal cells are isomorphic except in three species, Z. bartramioides, Z. chilensis and Z. pentastichus, where they are arranged in dimorphic longitudinal bands of 2–9 rows of yellowish, nodulose, thickwalled cells alternating with 2–6 rows of lighter, hyaline, straight, thin-walled cells. Previously this character was only noticed for Z. pentastichus, and considered of no taxonomic value. However, species exhibiting this basal cell pattern share other leaf laminal and sporophytic features, which support their segregation in a distinct group at the infrageneric rank, as sect. Stenomitrium. Perichaetial leaves.—In most Zygodon species the perichaetial leaves are not or only slightly differentiated, and such is the case among the treated species Z. menziesii, Z. intermedius, Z. jaffuelii and Z. papillatus. In other species the perichaetial leaves are differentiated from upper vegetative ones in morphology and areolation, usually having longer, smooth or slightly papillose cells. Zygodon pentastichus, Z. bartramioides, Z. chilensis, Z. pichinchensis, Z. reinwardtii, Z. hookeri var. hookeri and Z. hookeri var. leptobolax clearly show this differentiation, while in Z. obtusifolius it is less evident. This character, despite its taxonomic value at specific level, has not usually been used in keys because most specimens lack mature perichaetial leaves. Propagula.—In the Orthotrichaceae, propagula are not common but in Zygodon, where most species have them, only Z. pichinchensis and Z. pentastichus 458 the bryologist 109(4): 2006 Figure 2. Leaf basal cells. A. Zygodon reinwardtii (Skottsberg 435, S). B. Z. hookeri var. hookeri (Matteri & Schiavone CM 4910, BA). C. Z. obtusifolius (Cleef 6062, G). D. Z. bartramioides (Schwabe 61, JE-HERZOG). E, F. Z. pentastichus (Hosseus 171, JE). Scale A–D, F: 25 lm; E: 0, 25 mm. among the treated species lack them. Another distinctive feature is that in other Orthotrichaceae the propagula develop on leaves or, rarely, on rhizoids, while in Zygodon they typically originate in leaf axils. Propagulum length varies between 30–270 lm and is characteristic for each species. Fig. 3 compares propagulum size and shape in some of the treated species. Abundance of propagula is also variable. Zygodon hookeri var. hookeri, Z. reinwardtii and Z. intermedius have few propagula, or sometimes lack them all together, and moreover are difficult to see because they are hyaline to greenish-hyaline. In contrast, propagula are frequent and abundant in Z. bartramioides, Z. jaffuelii and Z. hookeri var. leptobolax, and very abundant and evident in Z. magellanicus, Z. papillatus and Z. chilensis. Traditionally, propagula represent an important source of taxonomic characters, especially when plants are sterile, because of their morphological diversification and common appearance. Shape, size, Calabrese: Zygodon in southern South America 459 Figure 3. Propagula. A. Zygodon reinwardtii (Ule 131, G). B. Z. jaffuelii (RP-6-2285-1b, MO). C. Z. papillatus (lack collector data, FH). D. Z. magellanicus (Dusén 83, S). E. Z. menziesii (Matteri & Schiavone CM 3768, BA). F. Z. bartramioides (Dusén 362, S). Scale: 30 lm. color, number per plant and cell organization are of great use in naming Zygodon species. Malta (1926) recognized two basic types of propagula based on their structure: those with only transverse septa, and those with transverse and longitudinal septa. However, in this study I have found a more complex pattern of propagule morphology, with three main types: a) Fusiform to fusiform-clavate, generally of 3–5 cells, with transverse septa and seldom some longitudinal ones, usually hyaline, rarely brown (Z. jaffuelii). It is the most common type in the genus, seen, among the treated species, in Z. hookeri var. hookeri, Z. hookeri var. leptobolax, Z. intermedius, Z. reinwardtii and Z. jafuelii (Fig. 3A–B). b) Cylindrical to cylindrical-clavate, of 4 or more cells, with transverse septa or with some longitudinal septa in the apical or basal cells, or both. It is the most common type in subg. Codonoblepharon. Species from the Andean-Patagonian and Fuegian regions with this type of propagula are Z. bartramioides, Z. menziesii and Z. obtusifolius, with only transverse septa and hyaline walls, and Z. chilensis, with brownish cells, except often the 460 the bryologist 109(4): 2006 apical and basal hyaline cells occasionally with some longitudinal septa (Fig. 3E–F). c) Ovoid to clavate, with a variable number of cells, with transverse and longitudinal septa, reddishbrown to yellowish-brown. This type is only found in some local species of sect. Zygodon, Z. magellanicus (Fig. 3D) and Z. papillatus (Fig. 3C). Although similar in structure, propagula of Z. papillatus are smaller, more ovoid and with walls lighter in color than propagula of Z. magellanicus. Branched propagula have only seldom been observed in Z. chilensis (Fig. 12H). Exceptional in the Orthotrichaceae, branched propagula are only known in Orthotrichum lyellii Hook. & Taylor, O. obtusifolium Brid. and O. gymnostomum Brid. Reproductive organs.—Distribution of gametangia is variable in Zygodon and of taxonomic importance. While in other Orthotrichaceae, such as Orthotrichum and Ulota D. Mohr, an autoicous sexual condition is the rule, most Zygodon species are dioicous, while some are autoicous (e.g., Z. obtusifolius), and even fewer synoicous (e.g., Z. reinwardtii). Malta (1926) discussed the heteroicous sexual condition, although this is only a funtional character. He described three types of ‘‘flowers’’ in Zygodon reinwardtii: ‘‘female flowers’’ (antheridia absent or reduced and 3–4 archegonia, of which only one is fertilized), ‘‘male flowers’’ (10–25 antheridia and 1–2 archegonia usually not fertilized), and ‘‘hermaphrodite flowers’’ (2–5 antheridia and 3–4 archegonia, of which usually only one is fertilized). In fact, all this cases represent the synoicous sexual condition, although likely they are functionally unisexual when archegonia or antheridia are reduced. I have observed hermaphroditic buds only in specimens of Z. reinwardtii. Finally, in the usually synoicous Z. hookeri var. hookeri I once found separated perichaetia and perigonia in the same plant. Gametangia are usually terminal in stems. Nevertheless, Malta (1926) pointed out that in the dioicous Zygodon schenkei Broth. and Z. perichaetialis Herzog (not in the study area) perichaetia are 6 lateral on short branches. Vaginula.—Little is known about the vaginula in Zygodon, as it has been seldom included in formal descriptions. Vaginulae can have persistent uniseriate paraphyses (e.g., Z. hookeri) or be naked (occasionally with some short paraphyses) as in Z. obtusifolius and species of subg. Codonoblepharon. Malta (1926) also indicated that sometimes the upper part of the vaginula has robust and persistent hairs (e.g., Z. trichomitrius and Z. pilosulus Müll. Hal.), and suggested a close relationship between persistence of these hairs and a pilose calyptra, because the two species have calyptrae with uniseriate hairs. Ochreae in Zygodon are typically very short and almost undifferentiated. Calyptra.—The calyptra is typically cucullate, smooth and naked, the latter frequently used to distinguish Zygodon from other Orthotrichaceae. However, there are three species with pilose calyptrae: Z. trichomitrius and Z. erosus Mitt. from South Africa, and Z. pilosulus from South America. The calyptra of Z. obtusifolius has been described as having prorate cells toward the apex (Goffinet & Vitt 1998), and thus slightly papillose (Lewinsky 1990; Malta 1926). I could not confirm this because all the studied specimens of Z. obtusifolius lacked calyptrae because they fall soon after sporophyte maturation. Sporophyte. Seta.—Zygodon always has a relatively long, straight to slightly curved, usually yellowish to yellowish-brown, rarely reddish-brown seta. Torsion of the seta, despite its taxonomic importance, has not been previously considered in Zygodon treatments (Düll 1985; Lewinsky 1990; Malta 1926; Vitt 1970, 1984), and only Vitt et al. (1993) used it to separate Zygodon, Orthotrichum, Ulota and Groutiella from other Orthotrichaceae. Most Zygodon species have setae that are distally dextrorse (twisted to the right, clockwise when seen from the apex) and proximally sinistrorse (twisted to the left, counterclockwise when seen from apex). Distally sinistrose setae were considered crucial by Goffinet and Vitt (1998) to segregate Zygodon pentastichus at the generic rank as Stenomitrium. However, I have found distally sinistrorse setae in three additional species (Table 1). Two of them, Z. bartramioides and Z. chilensis, which clearly belong in Zygodon, share with Z. pentastichus ovate distal cells with 2–4 thick papillae and basal cells in dimorphic bands, which indicates a taxonomic relationship, and that they would be the nexus between Z. pentastichus Calabrese: Zygodon in southern South America 461 Table 1. Setae torsion in Andean-Patagonian and Fuegian Zygodon. Torsion of the seta Species Subg. Codonoblepharon Z. menziesii Subg. Zygodon sect. Zygodon Z. Z. Z. Z. Z. Z. Z. Subg. Zygodon sect. Stenomitrium Subg. Obtusifolium jaffuelii intermedius pichinchensis papillatus reinwardtii hookeri var. hookeri hookeri var. leptobolax Z. bartramioides Z. pentastichus Z. chilensis Z. obtusifolius and Zygodon s.str. Finally, Z. obtusifolius also has distally sinistrorse setae. The basal part of the seta is sinistrorse in most Zygodon species, although some specimens of Z. pentastichus and Z. bartramioides have setae without torsion proximally, and Z. chilensis always has setae dextrorse at the base. Capsule.—Zygodon has exserted capsules, typically erect and eight-ribbed throughout. Despite the apparent homogeneity, capsules can be 6 cylindrical, ovoid or ellipsoid to fusiform, and its shape can be used in species recognition. The exothecial cells are rectangular, differentiated in bands of 3–6 columns of thick-walled cells corresponding to the ribs that alternate with bands of thin-walled cells. Stomata are superficial and invariably present in the lower part of the urn and the neck. Operculum.—In Zygodon the operculum always has a conic base and usually an oblique beak that varies from short-rostrate (e.g., Zygodon papillatus) to long-rostrate (e.g., Z. hookeri). Sometimes it is useful for species recognition, because the rostrum is extraordinarily long in some species (e.g., Z. pichinchensis or Z. reinwardtii) and in others very short (e.g., Z. papillatus or Z. obtusifolius). Peristome.—The peristome of Zygodon is arthrodontous and diplolepideous as in all Orthotrichaceae. It could have been derived from a peristome with an exostome of 16 free teeth more thickened on the OPL (outer peristomial layer) than on the PPL (primary In the distal part In the basal part dextrose sinistrorse sinistrorse Sinistrorse or without torsion dextrorse sinistrorse peristomial layer), and an endostome of 16 segments (Goffinet & Vitt 1998; Vitt 1981). In Zygodon, the more complex peristome has sixteen exostomial teeth and sixteen endostomial segments alternating with the teeth, usually united at base by a low connective membrane. Some species with this type of peristome also have a preperistome or prostome (Lewinsky 1990; Malta 1926). One of the most remarkable tendencies in Zygodon is the gradual loss of the exostome, from a slight reduction to its complete disappearance, giving rise to simple peristomes formed only by endostomial segments. These segments can also undergo reduction, and thus it is possible to find endostomial segments well developed, one or two cells wide, or even rudimentary. As a consequence of exostome and endostome reductions, the following peristomial combinations are known in Zygodon: a) 8 pairs of exostomial teeth and 8 pairs of endostomial segments (e.g., Z. pentastichus, Fig. 9A) b) 8 pairs of exostomial teeth and an endostome with 8 well-developed segments and to 8 weaker intercalary segments (e.g., Z. obtusifolius, Figs. 6I, 7A) c) 8 pairs of exostomial teeth and 8 well-developed endostomial segments (e.g., Z. chilensis, Figs. 12I, 13A) d) 8 pairs of exostomial teeth diversely reduced and 8 well-developed endostomial segments (e.g., Z. intermedius, Fig. 18A) 462 the bryologist 109(4): 2006 e) peristome of only 8 well-developed segments (e.g., Z. reinwardtii, Fig. 20K) f) peristome of only 8 reduced segments (e.g., Z. papillatus, Fig. 15J) g) total absence of peristome (none in the study area, e.g., the Holarctic Z. viridissimus) This reductional series can be symbolized by the following scheme: 8p/16 ! 8p/8þ8 ! 8p/8þn ! 8p/8 ! 8pred./8 ! 0/8 ! 0/8red. ! 0/0 double peristomes single peristomes Exostome teeth are reflexed or recurved when dry, while endostome segments are 6 erect or incurved. The teeth and the segments have hygroscopic movements that help spore liberation. According to Koponen (1978), the structure of the peristome is related to hygroscopic movements; exostomes of equal thickness on the external and internal surfaces are erect, while exostomes thicker on the external side are reflexed or recurved. According to Lewinsky (1990), the type of ornamentation has influence on exostome movement. For the present work I used light microscopy and SEM, and confirm that exostome teeth are ornamented on both the external (OPL) and the internal (PPL) surfaces, and that the ornamentation of the two is different. Usually the OPL has a basal reticulum that varies from smooth to papillose, while the exostomial PPL is often ornamented by papillae irregularly arranged or 6 aligned, according to the species. Among the treated species, only Z. intermedius has the exostome teeth (that are very reduced) with completely smooth cells. Also the endostome segments usually differ in surface ornamentation: while the endostomial PPL is often smooth or weakly ornamented, the IPL is often papillose, mostly at base. When the endostomial segments are reduced (Z. papillatus and all the synoicous taxa) both PPL and IPL surfaces are completely smooth. The connective basal membrane usually has a similar ornamentation to that of the base of the endostomial segments. As has been already indicated, in Zygodon papillatus and the synoicous species of the study area, peristomes can show great reduction. Spore liberation in these taxa is thus controlled by the capsule through the strong longitudinal ribs that reach the mouth. When dry, the contraction of the ribs closes the capsule mouth, further blocked by the approximation of the endostomial segments; when moist, the capsule mouth opens, separating the endostomial segments, which makes possible the liberation of the spores. This mechanism allows for spore liberation only under moist environmental conditions. As indicated by Lara et al. (1999), this morpho-functional adaptation to hygrocastique spore liberation, is also known in other Orthotrichaceae, such as Macromitrium Brid., Orthomitrium Lewinsky-Haapasaari & Crosby and Orthotrichum. Considering other characters, not all the species of Zygodon with exostomial reduction are closely related, which points to morphological convergence that has evolved independently in several groups of the family. Spores.—All Zygodon species are isosporous. Spores are spherical, sometimes slightly flattened, and usually have an ornamented surface. In the Andean Patagonian and Fuegian species spores are papillose (Z. pentastichus, Z. pichinchensis, Z. jaffuelii, Z. intermedius, Z. papillatus, Z. reiwardtii, Z. hookeri var. hookeri and Z. hookeri var. leptobolax); foveolate (Z. bartramioides and Z. chilensis); or smooth (Z. menziesii and Z. obtusifolius). According to size and presence of trilete mark, species can be included in two groups: a) spores 10–15 lm in diameter, usually with a trilete mark characterize Z. papillatus, Z. jaffuelii, Z. obtusifolius, Z. menziesii, Z. bartramioides and Z. chilensis; and b) spores more than 15 lm in diameter without a trilete mark characterize Z. pichinchensis, Z. intermedius, Z. pentastichus, Z. reinwardtii and Z. hookeri. TAXONOMIC TREATMENT Zygodon Hook. & Taylor, Muscol. Brit. 70. 1818. TYPE: Zygodon conoideus (Dicks.) Hook. & Taylor [basionym: Bryum conoideum Dicks.] Pleurozygodontopsis Dixon, Ann. Bryol. 12: 51. 1939. TYPE: P. decurrens Dixon Bryomaltaea Goffinet, Bryology for the Twentyfirst Century 151. 1998. TYPE: B. obtusifolia (Hook.) Goffinet [basionym: Zygodon obtusifolius Hook.] Codonoblepharon Schwägr., Spec. Musc. Frond., Suppl. 2(2): 142, tab. 137. 1824. TYPE: C. menziesii Schwägr. Stenomitrium (Mitt.) Broth., Nat. Pflanzenfam. Calabrese: Zygodon in southern South America 1(3): 464. 1902 [1903]. TYPE: S. pentastichum (Mont.) Broth. [basionym: Aulacomnium pentastichum Mont.] Description. Plants 0.2–15 cm tall, in turfs, rarely mats, light-green to olive-green, occasionally darkgreen or reddish-brown, growing on bark or rock, rarely on soil, mortar or cement. Stems erect, rarely prostrate, simple or branched, rounded to pentagonal in cross section; cortex of small, thick-walled cells, in 1–3 layers around large, isodiametric, thin-walled, undifferentiated cells. Rhizoids yellowish-brown to reddish-brown, exceptionally hyaline, smooth, roughened or papillose, sometimes covering the stem as a reddish-brown tomentum. Leaves appressed or 6 twisted when dry, erect-spreading to squarroserecurved when moist, sometimes undulate, typically keeled, 0.5–3 3 0.15–0.9 mm, ovate-lanceolate to linear-lanceolate, lanceolate-rhomboidal or lingulate, sometimes decurrent; lamina unistratose or partially bistratose; apex acute, rarely rounded-obtuse; margins undifferentiated, usually plane, rarely recurved (especially in the middle and lower parts of leaf), entire, papillose or papillose-crenulate, rarely spiculose, sometimes denticulate to dentate at the apex; upper laminal cells 6 isodiametric, rounded-hexagonal to subquadrate or ovate, plane, rarely bulging, papillose or smooth, thick-walled, 8–15(27) lm in diameter; papillae usually simple, occasionally branched, blunt, acute or subacute, 1–9 per cell; basal cells shortrectangular to elongate, rarely isodiametric, smooth or with scarce papillae, thin- or thick-walled, sometimes nodulose, hyaline or yellowish, isomorphic or dimorphic; costa simple, usually ending below the apex, rarely percurrent or excurrent, usually in a deep furrow, with superficial elongate cells, dorsally smooth or papillose, usually smooth in the ventral surface, in section with two ventral guide cells and dorsal stereids, rarely with 6 homogeneous cells. Propagula often present in leaves axils, cylindrical, fusiform, clavate or ovoid, with only transverse septa or with transverse and longitudinal septa, hyaline or yellowish-brown to reddish-brown walls. Dioicous, synoicous or autoicous. Perigonia axillary or terminal; leaves concave, ovate, apex acute. Perichaetia terminal; leaves differentiated or not from stem leaves, usually lanceolate to linear-lanceolate with acute, rarely rounded-obtuse apex. Vaginula glabrous or pilose. Seta long, erect to slightly curved, distally 463 dextrorse or sinistrorse, usually sinistrorse in the basal part, exceptionally without torsion or dextrorse at base, often yellowish-brown; capsule exserted, erect, ovoid, ellipsoidal or cylindrical, with 8 longitudinal strong ribs when dry, sometimes slightly contracted below the mouth, with phaneropore stomata in lower part of urn and neck; exothecial cells of the ribs differentiated; operculum conic at base, short to longrostrate, beak straight or oblique; annulus absent; peristome double, single or absent; exostome teeth partially or completely united in 8 pairs, ornamented, reflexed or appressed to the capsule when dry, OPL papillose, papillose-striate, smooth-reticulate, papillose-reticulate or papillose-lamellate, PPL papillose, papillose-striate or almost smooth; prostome very rarely present; endostome of 8 or 16 free segments alternating with exostome teeth, usually united by a low basal membrane, rarely fused in the lower 1/3, inflexed, smooth or ornamented, PPL usually smooth, occasionally slightly striate or with disperse papillae, IPL smooth, papillose or papillose-striate. Calyptra conical, cucullate, glabrous and smooth, rarely pilose or slightly papillose, covering the upper 2/3 of the capsule. Spores 10–30 lm in diameter, papillose, foveolate or smooth, trilete mark distinct or not. Ecology. Species of Zygodon usually grow on trees, stumps, also or exclusively on rocks, and rarely on soil, exposed roots of old trees, sand, mortar or concrete. Habitat information is scarce for the treated species, and most data are derived from field work by the author. In southern South America, they are most common in the Andean Nothofagus forests, from sea level to 6 1100 m, always in rather humid places, also near streams or lakes in riparian N. antarctica forests, while some species grow in more open and exposed areas, such as the northern Patagonian NothofagusAustrocedrus mixed forests, that to the east contact with steppe vegetation. Zygodon species commonly grow on the native Austrocedrus chilensis, Araucaria araucana, Fitzroya cupressoides, Nothofagus spp. and Podocarpus nubigena, and some shrubs, mainly Berberis. Exotic trees are exceptional, with only one report of Z. bartramioides growing on Eucalyptus. In other areas of America, such as Mexico, Venezuela and Colombia, Zygodon grows at 1000– 4500 m, from the Andean forests to the desert in Colombia (Churchill & Linares 1995), and Quercus 464 the bryologist 109(4): 2006 Table 2. Taxa from the study area and their correspondence with other taxa previously reported. Taxa previously reported from the study area Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. Z. menziesii (Schwägr.) Arnott corralensis Lor. obtusifolius Hook. obtusifolius var. antarcticus Malta pentastichus (Mont.) Müll. Hal. pentastichus var. crispatulus (Thér.) Malta pentastichus var. strictifolius Malta bartramioides Malta tristis Herzog jaffuelii Thér. liebmannii Schimp. pichinchensis (Taylor) Mitt. magellanicus Malta papillatus Mont. intermedius Bruch & Schimp. reinwardtii (Hornsch. )A. Braun reinwardtii var. hyadesii (Besch.) Malta hookeri Hampe inermis Malta theriotii Herzog Taxa accepted in this work Taxa previously reported from other areas Z. menziesii (Schwägr.) Arnott Z. obtusifolius Hook. Z. pentastichus (Mont.) Müll. Hal. Z. bartramioides Malta Z. jaffuelii Thér. excluded Z. pichinchensis (Taylor) Mitt. Z. magellanicus Malta Z. papillatus Mont. Z. intermedius Bruch & Schimp. Z. reinwardtii (Hornsch.) Bruch & Schimp. Z. hookeri Hampe Z. hookeri var. leptobolax (Müll. Hal) Calabrese Z. chilensis Calabrese & Lara and Abies forests in Mexico (Vitt 1994). Lewinsky (1990) provided a thorough description of Australasian Zygodon habitats, while Düll (1985), LewinskyHaapasaari (1998) and Smith (2004) describe the European and Macaronesian habitats. Distribution. According to Index Muscorum (Wijk et al. 1969), Zygodon includes 90 species, of which more than 50 are distributed in the tropics and subtropics, while the rest are distributed in the temperate regions of both hemispheres. The Andean region, with 49 species reported, can be considered the main center of diversity for the genus. For the Andean-Patagonian and Fuegian regions I recognize 13 taxa (Table 2). Five of them are endemic (38.5%): Z. bartramioides, Z. chilensis, Z. jaffuelii, Z. magellanicus and Z. papillatus. Andean species are Z. pentastichus (from Peru to 478S in Patagonia and the Juan Fernández Islands) and Z. pichinchensis (throughout the Andes and Mexico). Zygodon menziesii and Z. hookeri var. hookeri (Australia, New Zealand and southern South America), as well as Z. hookeri var. leptobolax (South Africa and southern South America) show a sub-Antarctic Z. leptobolax Müll. Hal. (South Africa) distribution. Finally, widespread in the Southern Hemisphere are Z. intermedius, Z. obtusifolius and Z. reinwardtii, the latter also known from Central and South America, and with isolated reports that need confirmation for Alaska (very doubtful, but cf. Worley & Iwatsuki 1970), Madagascar (Crosby et al. 1983), Philippines (Tan & Iwatsuki 1991), and Tasmania (Dalton et al. 1991; but see Lewinsky 1990, who did not mention it for Australasia). Although it can be argued that the number of species treated here is low, they are highly representative within the genus and allow one to understand the relationships between taxa in a wider context. Indeed, the analysis of taxonomic characters suggests that the four genera that have been segregated from Zygodon (Bryomaltaea, Codonoblepharon, Stenomitrium and Zygodon s.str.) have more similarities than differences from each other, and no clear separation can be established between them when the variability of the group is analyzed as a whole. As a consequence, these four taxa are here considered as part of a broadly conceived Zygodon, for which a new infrageneric classification is proposed, including three Calabrese: Zygodon in southern South America 465 Table 3. Historical outline of infrageneric classification of the genus Zygodon and the classification proposed in the present work. Brotherus (1902–1903) Malta (1923, 1926) Goffinet & Vitt (1998) Goffinet et al. (2004) Gen. Gen. Gen. Gen. Zygodon Stenomitrium Zygodon Zygodon Sect. Sect. Sect. Sect. Zygodon Stenomitrium Obtusifolii Bryoides Gen. Gen. Gen. Gen. Zygodon Stenomitrium Bryomaltaea Codonoblepharon subgenera, one with two sections. Table 3 shows the historical outline of the infrageneric classifications as well as the new classification proposed here. A Synoptic Key to Infrageneric Taxa. 1. Leaf cells smooth.................. Subg. Codonoblepharon (p. 466) 1’. Upper laminal cells papillose ..................................................2 2. Laminal cells bulging; leaf apex rounded-obtuse.......... .............................................Subg. Obtusifolium (p. 469) 2’. Laminal cells plane; leaf apex acute to acuminate, exceptionally rounded-obtuse...........(Subg. Zygodon) 3 3. Leaf basal cells dimorphic, porose and thick-walled cells alternating with bands of straight and thin-walled cells; seta distally sinistrorse; peristome double ....................................... ...................................................... Sect. Stenomitrium (p. 474) 3’. Leaf basal cells never dimorphic, not in differentiated bands; seta distally dextrorse; peristome double, single or absent ..............................................................Sect. Zygodon (p. 484) Key to Andean-Patagonian and Fuegian Taxa of Zygodon. 1. Laminal cells smooth; propagula cylindrical, with only transverse septa; peristome double......... 1. Zygodon menziesii 1’. Laminal cells papillose; propagula fusiform, cylindrical, clavate or ovoid, with only transverse septa or with transverse and longitudinal septa; peristome double or single ........................................................................................2 2. Laminal cells bulging; basal cells morphologically undifferentiated from upper cells, except for the presence of papillae; apex rounded-obtuse; peristome double; autoicous................................... 2. Z. obtusifolius 2’. Laminal cells plane; basal cells morphologically differentiated from upper cells; apex acute to acuminate; peristome double or single; dioicous or synoicous ....3 3. Basal leaf cells dimorphic in definite bands; stems erect or prostrate; leaves clearly 5-ranked; setae distally sinistrorse; peristome double.......................................................................4 3’. Basal leaf cells not in bands of different colors; stems erect; leaves not or weakly 5-ranked; setae distally dextrorse; peristome double or simple ....................................................6 4. Stems prostrate with erect branches; leaves more than 2 mm long; spores large, 17–28 lm in diameter, papillose .................................................3. Z. pentastichus Gen. Leratia p.p. Proposed classification Subg. Zygodon Sect. Zygodon Sect. Stenomitrium Subg. Obtusifolium Subg. Codonoblepharon 4’. Stems erect; leaves less than 2 mm long; spores small, 10–12 lm, foveolate .......................................................5 5. Leaves lanceolate-rhomboidal; propagula 40–67 3 15–23 lm, hyaline, usually of 4 cells, with only transverse septa; setae 2– 5 mm long ................................................... 4. Z. bartramioides 5’. Leaves lanceolate to narrow-lanceolate; propagula (75–)87– 120 3 24–30 lm, usually with colored walls, of 4–9 cells, with transverse septa and sometimes also longitudinal septa; setae ca. 10 mm long.......................................... 5. Z. chilensis 6. Dioicous; peristome double or single; spores than 18 lm .....................................................................................7 6’. Synoicous; peristome simple, reduced to 8 short endostomial segments; spores usually more than 18 lm ............................. (Z. reinwardtii-hookeri group) 11 7. Propagula clavate to oblong-clavate, with transverse and longitudinal septa, colored, abundant ....................................8 7’. Propagula fusiform to clavate, without longitudinal septa, hyaline or colored, or plants without propagula..................9 8. Propagula large, 50–90 3 30–39 lm, reddish-brown; rhizoids roughened or papillose; laminal cells with simple papillae......................................6. Z. magellanicus 8’. Propagula small, 19–32 3 17–25 lm, yellowish-brown; rhizoids smooth; laminal cells with branched papillae ...................................................................7. Z. papillatus 9. Leaf margins spinulose by large conic papillae; papillae acute or subacute; plants without propagula; peristome simple ....................................................................... 8. Z. pichinchensis 9’. Leaf margins papillose; papillae low; plants with propagula; peristome double ..................................................................10 10. Propagula hyaline, fusiform, scarce; peristome double with reduced exostome of smooth or almost smooth cells ....................................................... 9. Z. intermedius 10’. Propagula colored when mature, clavate, abundant; peristome double with exostome of 8 pairs of teeth distally truncate and ornamented ......... 10. Z. jaffuelii 11. Leaf apex dentate, sometimes denticulate; leaves distinctly decurrent; spores (15–)18–25 lm; capsules often fusiform, sometimes asymmetric................................ 11. Z. reinwardtii 11’. Leaf apex entire or denticulate; leaves decurrent, at least slightly; spores (18–)20–30 lm; capsules cylindrical ............................................................. (12. Z. hookeri s.l.) 12 12. Leaf apex often denticulate; margins undulate; propagula scarce, 36–52 3 12–20 lm, consisting of 3 cells ......................................12a. Z. hookeri var. hookeri 466 the bryologist 109(4): 2006 12’. Leaf apex usually entire; margins usually plane; propagula abundant, 45–81(90) 3 16–30 lm, usually consisisting of 3–5 cells12b. Z. hookeri var. leptobolax Subg. Codonoblepharon (Schwägr.) Calabrese, stat. nov. Codonoblepharon Schwägr., Spec. Musc. Frond., Suppl. 2(2): 142, tab. 137. 1824; Zygodon sect. Codonoblepharon (Schwägr.) Müll. Hal., Linnaea 18: 669. 1845; Zygodon sect. Bryoides Malta, Latvijas Univ. Raksti 6: 281. 1923. TYPE: C. menziesii Schwägr. Diagnosis. Plants to 2 cm tall, growing on bark or rock. Stems erect. Leaves lanceolate; apex acute; cells smooth, not bulging. Propagula cylindrical, with transverse septa (except Zygodon menziesii var. angustifolius very rarely with longitudinal septa). Dioicous or autoicous. Seta dextrorse distally, sinistrorse at base. Peristome double. Spores small, less than 18 lm in diameter, smooth, trilete mark distinct. Discussion. This subgenus is defined by the smooth laminal cells. This difference led Goffinet and Vitt (1998) to re-establish Codonoblepharon as an independent genus, a view accepted by Matcham and O’Shea (2005). However, species of this group share with other Zygodon species the unique propagula, the cucullate calyptra, ribbed capsules, as well as the structure of the double peristome, with 8 pairs of teeth and 8 endostomial segments keeled and alternate with exostomial teeth, which in my opinion justify the maintenance of these species in Zygodon, although at subgeneric rank. Further support for my taxonomic arrangement is the position of Z. forsteri, which shows all previous characters but formerly excluded from Codonoblepharon by Goffinet and Vitt (1998), later included on the basis of molecular evidence (Goffinet et al. 2004), and again excluded by Matcham and O’Shea (2005) on the basis of its white rhizoids, wider cells and north temperate distribution. Previous to this study Zygodon subg. Codonoblepharon was considered to include two species in the area: Zygodon menziesii (He 1998; Matteri 1989) and Z. corralensis (He 1998). The latter was considered endemic to southern South America, but Calabrese (2003) and Matcham and O’Shea (2005) clearly demonstrated that it is a synonym of Z. menziesii. 1. Zygodon menziesii (Schwägr.) Arnott, Mém. Soc. Linn. Paris 5: 233. 1827; Codonoblepharon menziesii Schwägr., Spec. Musc. Frond., Suppl. 2 (2): 142, tab. 137. 1824. Ind. loc.: ‘‘In nova Seelandia ad cortices legit cl. Archibald Menzies.’’ TYPE: NEW ZEALAND. STEWART ISLAND: Half Moon Bay, Jun 1889, Bell 679 (neotype, here designated, CHR 527696!). NOTE: The type material of Z. menziesii, kept at G, was lost by the postal service (P. Geissler, pers. comm., March 1, 2000). Zygodon drummondii Taylor, London J. Bot. 5: 46. 1846. TYPE: ‘‘Australia, Swan River, Drummond 1843’’ (isotypes, BM!, H, L). Synonymized by Wilson (1846: 449). Zygodon corralensis Lorentz, Bot. Zeitung (Berlin) 24: 187. 1866. TYPE: ‘‘Chile, Valdivia, Corral, an den Kalkmauern der Hafenfestung, Dr. Krause’’ (isotype, NY!). Synonymized by Matcham and O’Shea (2005: 130). Zygodon menziesii var. angustifolius Malta, Latvijas Univ. Raksti 10: 317. 1924. TYPE: ‘‘Neuseeland: Mauriceville (Gray).’’ (Lectotype, designated here, Gray 47, BM!; syntypes, Gray 9, Gray 50, all BM!), syn. nov. Illustrations. Figs. 1F, 3E, 4–5. Description. Plants slender, 0.5–2.0 cm tall, in dense turfs, green above, brown to reddish-brown below. Stems erect, branched. Rhizoids reddishbrown, roughened. Leaves twisted when dry, erect when moist, 0.6–1.8(2.1) 3 0.2–0.5 mm, lanceolate to lingulate, not decurrent, apex acute; margins plane or recurved in lower 1/2–2/3, rarely bistratose, entire and completely smooth; laminal cells smooth; upper leaf cells sub-quadrate to shortly ellipsoidal or rhomboidal, with 6 thickened walls, 8–12 3 7–12 lm; lower leaf cells sub-quadrate to rectangular, longer, 15–45 3 10–20 lm, with a group of globose basal cells; costa ending below the apex, typically reddish, 30–57 lm wide in the lower 1/3, with elongate, smooth cells, in section with 2 ventral guide cells and dorsal stereids. Propagula on reddish-brown axillary stalks, cylindrical, usually hyaline, greenish or yellowish-brown, 53–92 3 14–21 lm, (3–)4–7(9)celled, only with transverse septa. Dioicous. Perichaetial leaves undifferentiated. Seta (2.5–)4–6(8) mm long, dextrorse in the distal part and sinistrorse to the base; capsule exserted, erect, ellipsoidal to pyriform, ca. 1.5 mm long, with 8 longitudinal ribs along the entire capsule length when dry; exothecial bands differentiated, of 4–5 cell rows each; operculum conical at base, shortly rostrate and curved; peristome Calabrese: Zygodon in southern South America 467 Figure 4. Zygodon menziesii. A. Habit when dry. B. Habit when moist. C. Capsule when dry. D. Leaves. E. Leaf apex. F. Leaf basal cells. G. Leaf cross-sections. H. Propagula. I. Peristome (inner view). J. Spores. A, C from Allison 2263 (CHR); B, dII, F, H from Schwabe 81 (S-B1887); dI from C. & I. Skottsberg 371 (S); dIII, E, gI from Matteri & Schiavone CM 3768 (BA); dIV from Bell 679 (HII BROTHERUS); g from Skottsberg 371 (S); I, J from Matteri CM 1534-b (BA). 468 the bryologist 109(4): 2006 Figure 5. Zygodon menziesii. SEM photographs of peristome. A. Lateral view of the capsule mouth and peristome. B–D. Exostome. B. OPL, basal. C. PPL, middle portion of teeth. D. PPL, apical. E, F. Endostome. E. PPL. F. Details of IPL ornamentation in the basal portion of the segments. A–F from Norris 25598 (H). double; exostome of 8 pairs of teeth, recurved and appressed to the capsule when dry, dorsal surface (OPL) with papillae on a reticulum in the basal part and with papillae aligned or irregularly disposed above, ventral surface (PPL) papillose, with papillae longitudinally aligned in the lower 1/2–2/3, and confluent papillae irregularly disposed at the upper part; endostome of 8 segments dorsally keeled, sometimes appendiculate, occasionally with intercalary segments (8þn, 8þ8), PPL smooth, IPL with papillose lines obliquely oriented at the base, papillae longitudinally aligned at the central part, and papillae irregularly disposed (some of them merged) at the distal part, basal membrane low, continuous, striatepapillose. Spores almost smooth, 15–18 lm in diameter, trilete mark distinct. Ecology. Zygodon menziesii usually grows on rocks, more rarely on bark. In the Andean-Patagonian and Fuegian region it is found on mortar, concrete and bricks, and less frequently on bark. Few data are known Calabrese: Zygodon in southern South America on the phorophytes, as it has been reported only from ‘‘huahuán’’ (Laureliopsis philippiana (Looser) Schodde). In Australia and New Zealand it is frequently found on rock as well; however, it has been also collected on Eucalyptus, and more rarely, on Nothofagus. Distribution (Fig. 23A). The distribution of Zygodon menziesii is typically Subantarctic. It ranges from Australia, New Zealand and South Africa to southern South America. In the Andean-Patagonian and Fuegian region it is found in Argentina from Tierra del Fuego, and in Chile from Osorno, Valdivia and Chiloé, as well as in the Juan Fernández Islands. Differentiation. The subg. Codonoblepharon is represented in the study area only by Zygodon menziesii. Confusion of this species with any other in the genus is unlikely, because it lacks papillae on the leaf cells. Variability. Zygodon menziesii exhibits considerable gametophytic variability. Leaves are especially variable in size, width, margin recurvature, apex shape and costa robustness and color. Regarding leaf size, in some specimens they hardly exceed 0.6 3 0.2 mm (e.g., Skottsberg 371, S!) (Fig. 4dI), whereas in others they reach 1.8 3 0.5 mm (e.g., Streimann 58205, H!). Leaf margins are usually recurved in the lower 2/3, althought some specimens have plane margins, especially those extreme expressions with leaves either small and very narrow, or large and very wide. This variability was clearly pointed out by Lewinsky (1990: 127–129, figs. 101, 105, 111), and confirmed by my own observations. Shape of the apex is also variable; more often the leaves are wide and suddenly narrowed at apex, as reported by Malta (1926: 156, fig. 95d), but there are also leaves more gradually narrowed to the apex, even in the same plant. The costa is usually very wide in relation to the leaf width, and although its color can vary from greenish to reddish, it is typically reddish. Propagula are also variable. Some of them consist of 3– 4 cells, whereas others have 8–9 cells. Propagula are usually hyaline-green, but they can be also brownish. This variation is often present within the same collection (e.g., Matteri & Schiavone 3768, BA!). According to Malta (1924) and Lewinsky (1990), the New Zealand Z. menziesii var. angustifolius differs from the type variety by the presence of longitudinal septa in the propagula. However, most propagula in the type material exclusively have transverse septa, and only a few in Gray 47 (BM!) and Gray 50 (BM!) also have 469 longitudinal septa; moreover leaves in all the syntypes are narrowly lanceolate, similar to the leaves in Chilean materials of the type variety (e.g., Skottsberg 371, S!). Zygodon corralensis was described to include plants with narrower leaves gradually ending in an acute apex, and with smaller propagula than Z. menziesii. These features are variable in Z. menziesii, as stated above, and hardly usable to distinguish taxa. The type material of Z. corralensis and all the specimens identified as Z. corralensis, including the only other reported by Malta (Skottsberg 371, see Malta 1926: 158), fall within the range of variation of Z. menziesii. The specimen reported as Zygodon corralensis from South Africa (Arts 1998: 444) was not available for study, but according to the figure in Arts (1998) it could belong in Z. menziesii. Selected specimens examined (76). ARGENTINA. TIERRA DEL FUEGO: Isla de los Estados, Bahı́a Liberty, Matteri 1534 b (BA), Isla de Tierra del Fuego, Bahı́a Buen Suceso, extremo oriental del Morro Sur, 1-II1986, Matteri & Schiavone CM 3768 (BA). CHILE. REGIÓN V. VALPARAÍSO: Islas Juan Fernández, Masatierra, Valle Anson, Plazoleta, Skottsberg 371 (S). REGIÓN X. OSORNO: Yerbas Buenas, centro de recreación Las Cascadas, Administración, Mahu 22465 (MO 3987813); VALDIVIA: Corral bei Quitaluto, Hosseus 691 (JEHerzog); CHILOÉ: Chiloé, Lobb 37 (BM 555683a). REGIÓN XI: Puerto Puyuhuapi, Schwabe 1 (JE -Herzog). AUSTRALIA. SOUTH AUSTRALIA: Kangaroo Island, Cape du Couedic road, 1 km S of Rocky River Settlement, Flinders Chase National Park, 12 km NNE of Cape du Couedic, Streimann 55009, Musci Australasiae Exsicc. 468 (CHR 504018). TASMANIA: Deloraine, Scott 994 (BA). VICTORIA: Ewarts Road, Barandula Range, 16 km SSE of Wodonga, Streimann 15453 (H). WESTERN AUSTRALIA: along Collie River near Collie Burn, Norris 25598 (H). NEW ZEALAND. NORTH ISLAND: Tongariro National Park, Mt. Ruapehu, Okahune Mtn. Rd., Frahm 29–3 (CHR 492307). SOUTH ISLAND: Westland, Haast Pass, Frahm 8–23 (CHR 503116). STEWART ISLAND: Horseshoe Point, Deadman’s Beach, Fife 5977 (CHR 461652). EDERBY ISLAND: NNE of Sandy Bay, Vitt 8814 (CHR 447876). CHATHAM ISLAND: Awamata Stream, c. 10 km SW of Waitangi, Fife 11308 (CHR 514636). SUBG. Obtusifolium (Malta) Calabrese, stat. nov. Zygodon sect. Obtusifolii Malta, Latvijas Univ. Raksti 470 the bryologist 109(4): 2006 6: 282. 1923; Bryomaltaea Goffinet in Goffinet & Vitt, Bryology for the Twenty-first Century 151. 1998. TYPE: Zygodon obtusifolius Hook. Diagnosis. Plants small, 0.5–1.5 cm tall, in dense turfs, often on bark. Stems erect, usually branched. Leaves lingulate; apex rounded-obtuse; upper laminal cells isodiametric, bulging, with papillae often forked or fused, toward the base usually smooth or rarely papillose, mostly undifferentiated from upper cells. Propagula cylindrical, with only transverse septa. Autoicous. Seta sinistrorse throughout. Peristome double. Spores small, less than 15 lm in diameter, finely papillose, trilete mark distinct. Discussion. The diagnostic character for this subgenus is the bulging nature of the leaf cells. Mostly undifferentiated basal leaf cells are also rarely seen in the genus, and help to separate it from other subgenera. The subgenus only includes Zygodon obtusifolius, widespread in the Southern Hemisphere, South-East Asia, Central America and Mexico. Based on rbcL sequence data, Goffinet et al. (1998), suggested that Z. obtusifolius would be closely related to members of subfamily Macromitrioideae, while sections Zygodon and Bryoides would be resolved in another clade. Accordingly, the species was segregated in a new monospecific genus, Bryomaltaea Goffinet. Goffinet and Vitt (1998: 151) characterized Bryomaltaea by having obtuse, erect and appressed leaves. However, these features are also present in Zygodon conoideus (Dicks.) Hook. & Taylor var. lingulatus S. R. Edwards, a member of sect. Zygodon. According to Goffinet et al. (1998), the unexpected relation of Z. obtusifolius with the Macromitrioideae could be an artefact or an indication of chloroplast genome capture from a macromitrioid taxon. Goffinet and Vitt (1998) retained the genus Bryomaltaea close to Zygodon. Recently, Goffinet et al. (2004) based on nad5 sequence data, transferred Bryomaltaea obtusifolia to Leratia as L. obtusifolia (Hook.) Goffinet. These authors mentioned bulging laminal cells, seta torsion and prorate cells at the calyptra apex as the morphological characters shared by Bryomaltaea and Leratia. However, Leratia has totally smooth capsules while Zygodon obtusifolius has strongly ribbed ones as all other species of Zygodon. Torsion of the seta and calyptra have been previously discussed in this work (see taxonomic characters), and cannot be considered to separate Zygodon from Bryomaltea or Leratia. In a recent paper, Wilbraham and Long (2005) treated Z. obtusifolius in Bryomaltea, but considered Leratia as a distinct genus contrary to Goffinet et al. (2004). Finally, according to Goffinet et al. (2004), trnL-trnF, rps4, nad5 and LSU data are congruent with their earlier hypothesis that Zygodon obtusifolius may be related to the Macromitrioideae, and the clade including Bryomaltaea and Leratia may indicate a transition between Macromitrioideae and Orthotrichoideae (Goffinet et al. 2004). Zygodon obtusifolius shares with all other members of Zygodon the acrocarpic habit, cucullate calyptrae, all sporophytic features, and especially the unique propagula which, with the inconclusive molecular evidence, suggest that it is best treated at the subgeneric level within Zygodon. 2. Zygodon obtusifolius Hook., Musc. Exot. 2: CLIX. 1819. Codonoblepharon obtusifolium (Hook.) A. Jaeger, Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1872–73: 119 (Gen. Sp. Musc. 1: 397). 1874; Bryomaltaea obtusifolia (Hook.) Goffinet in Goffinet & Vitt, Bryology for the Twenty-first Century 151. 1998; Leratia obtusifolia (Hook.) Goffinet in Goffinet et al., Monogr. Syst. Bot. Missouri Bot. Gard. 98: 286. 2004. TYPE: ‘‘Hab. In Nepal. Hon. D. Gardner’’ (lectotype, designated by Lewinsky (1990), BM!). Codonoblepharon neglectum A. Jaeger, Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1872–73:118. 1874; Zygodon neglectus Hampe ex Müll. Hal., Hedwigia 37:133. 1898. TYPE: ‘‘Nova-Seelandia in fretu insularum (Colenso).’’ Synonymized by Malta (1926: 162). NOTE: Codonoblepharon neglectum has been considered an invalid name (nomen nudum) by most authors, who only considered the taxon validly published after Müll. Hal. described Zygodon neglectus (typified by ‘‘New Zealand, Knight’’) in 1898. However, A. Jaeger (1874: 118–119) considered the New Zealand material collected by Colenso distinct from Z. obtusifolius Hook., and described them as C. neglectum with a clear and direct reference to the description in Hooker (1855), which, according to the ICBN 32.1, 32.3, and 32.4 (St. Louis Code), makes the name validly published. Malta correctly considered C. neglectum validly described Calabrese: Zygodon in southern South America by A. Jaeger, but his views were apparently unnoticed by later authors. Zygodon linguiformis Müll. Hal., Bot. Zeitung (Berlin) 16:163. 1858; Zygodon linguaeformis Hampe ex Müll. Hal., Bull. Herb. Boissier 6: 95. 1898, nom. inval. orthogr. err.; Codonoblepharon linguiforme (Müll. Hal.) A. Jaeger, Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1872–73: 119. (Gen. Sp. Musc. 1:397). 1874. TYPE: ‘‘Columbia. Ad truncis arborum: Hampe donavit.’’ Synonymized by Malta (1926: 162). Zygodon spathulaefolius Besch., Mém. Soc. Sci. Nat. Cherbourg 16: 187. 1872. TYPE: ‘‘Mexico. Prope Mejico, in sylva della Desierta Vieja, sept. 1865, Bourg. n8 1334.’’ Synonymized by Malta (1926: 162). Zygodon erythrocarpus Müll. Hal., Linnaea 42: 365. 1879. TYPE: ‘‘Argentinia subtropica, Tucumán prope Siambon in truncis Alni ferruginei, c. fruct. maturis et cum Zygodonte ochraceo asociatus.’’ Synonymized by Malta (1926: 162). Zygodon araucariae Müll. Hal., Bull. Herb. Boissier 6: 95. 1898. TYPE: ‘‘Brasilia, Serra Geral, ad truncos Araucariae Brasiliensis, Junio 1890: E. Ule, Coll. N8 665; Minas Geraës, Serra Itatiaia, 1500 m. altus, ad truncos arborum in sylva, April 1894: E. Ule, Coll. N8 1918, in Bryotheca Brasiliensi N8 130 sub Zygod. linguaeformi Hpe., qui non invenitur.’’ (syntypes H-BR! ‘‘Ule 665;’’ BA-MATTERI! ‘‘Ule 665;’’ G-BOISSIER! ‘‘Ule, Bryotheca Brasiliensi N8 130’’ and ‘‘Ule, Junio 1890’’). Synonymized by Malta (1926: 162). Zygodon obtusifolius var. antarcticus Malta, Latvijas Univ. Raksti 10: 334, 1924. TYPE: CHILE. ‘‘Valparaı́so (Porter), Cordillera de la Costa supra Angol in truncis arborum (Dusén N8 845); [. . .] Corral, an Kalkmauern der Hafenfestung (Krause) [. . .]; o. n. O. (Sainthill) als Z. obtusifolius Hook.’’ (lectotype, here designated, ‘‘Dusén N8 845’’, S!), syn. nov. Zygodon obtusifolius var. latifolius Malta, Latvijas Univ. Raksti 10: 334, 1924. TYPE: ‘‘Mexico: Federal District, Cima 10,000 ft. (Pringle, Plantae mexicanae N8 10517 und 10540) als Z. spathulaefolius Besch.’’ (lectotype, here designated, ‘‘Pringle N8 10540,’’ G!), syn. nov. Zygodon asper Müll. Hal. ex Malta, Latvijas Univ. Bot. Dārza Darbi 1: 166. 1926, nom. nud. 471 Zygodon rufulus Dusén in Malta, Latvijas Univ. Bot. Dārza Darbi 1: 166. 1926, nom. nud. in syn. Illustrations. Figs. 1E, 2C, 6–7. Description. Plants slender, 0.5–1.5 cm tall, in dense turfs, olive-green to brownish above, reddishbrown to dark brown below. Stems erect, branched. Rhizoids yellowish-brown, smooth, well developed at base and extending up the stems. Leaves erect and keeled when dry, erect to erect-patent when moist, 0.5–0.9 3 0.15–0.3 mm, lingulate, base not decurrent, apex rounded-obtuse; margins plane or slightly recurved in the lower half, papillose-crenulate almost throughout; upper leaf cells isodiametric, thickwalled, (8–)9–10(13) lm in diameter, bulging, papillose, 2–3 papillae per cell; papillae low, blunt, sometimes forked or multiple (several papillae forming a complex single papilla); basal cells isodiametric, ca 10 lm in diameter, generally smooth, rarely papillose, especially towards the margins; costa ending below the apex, 30–48 lm wide in the lower 1/3, in a deep furrow, with superficial cells elongate becoming shorter towards the apex, dorsally papillose in the upper 2/3, ventrally covered by papillose and isodiametric laminal cells towards the apex, in section cells 6 homogeneous. Propagula cylindrical, usually hyaline, rarely yellowish-brown to greenish, 70–85 3 12–15(23) lm, (4–)6–8-celled, with only transverse septa. Autoicous. Perichaetial leaves slightly differentiated; margins plane; basal cells rectangular, more elongate than in stem leaves. Seta 5–15 mm long, sinistrorse throughout; capsule erect, ovoid to ellipsoidal, 1.0–1.5 mm long, with 8 longitudinal ribs; exothecial bands differentiated, of 4–5 cell rows each, interrupted by a continuous ring of 3–5 smaller cells surrounding capsule mouth; operculum conical at base, shortly rostrate; peristome double; exostome robust, of 8 pairs of teeth, reflexed or recurved and appressed to the capsule when dry, dorsal surface (OPL) reticulate, reticulum almost smooth to densely papillose, sometimes completely covered in the lower half with branched or simple papillae, coarsely papillose in the upper half, ventral surface (PPL) smooth to roughened-papillose in the lower 2/3, coarsely papillose at apex; endostome of 8 hyaline, dorsally keeled segments, occasionally with some extra segments, dorsal surface (PPL) smooth to slightly longitudinally striate throughout, ventral surface 472 the bryologist 109(4): 2006 Figure 6. Zygodon obtusifolius. A. Habit when dry. B. Habit when moist. C. Leaves. D. Apex. E. Leaf basal cells. F. Leaf cross-section. G. Propagula. H. Capsule when moist. I. Peristome (inner view). J. Spores. B–G from Dusén s.n. (S); A, H from Ule 665 (HBROTHERUS); I–J from Fendler 25 (G). (IPL) papillose, papillae in radial rows in basal cells, aligned or not in the middle and perfectly longitudinally aligned or not towards the apex, basal membrane low, continuous and striate. Spores finely papillose or almost smooth, 12–15 lm in diameter, trilete mark distinct. Ecology. Zygodon obtusifolius usually grows as epiphyte, more rarely on rocks, in dense or loose turfs. It has been found on trunks and roots of old trees (Araucaria, Quercus, Beilschmidia, Dracrydium and Weinmania), logs and occasionally on twigs of shrubs. Distribution (Fig. 23A). In America it ranges from Chile to Mexico. Also reported from Africa, Asia (Nepal, Sri Lanka) and Australasia (New Zealand and Tasmania). In the study area it is known from Región IX and Región X of Chile. Differentiation. Zygodon obtusifolius is easy to recognize by its leaves with bulging cells and roundedobtuse apex, unique features in the genus. The recently described Z. conoideus var. lingulatus (Edwards et al. 2000) also has rounded-obtuse leaf apices, but this is a dioicous Northern Hemisphere plant Calabrese: Zygodon in southern South America 473 Figure 7. Zygodon obtusifolius. SEM photographs of peristome. A. Peristome. B, C. Exostome. B. OPL, middle portion of teeth. C. PPL, basal and middle portion of teeth. D–F. Endostome. D. Outer surface of the segments, details of the PPL. E. IPL, basal. F. IPL, apical. A–F from Ule 665 (H-BROTHERUS). (only known from Surrey, U.K.) with flat laminal cells bearing simple papillae and marginal cells wider in the apex than in the medial part of leaves. Variability. Two varieties of Z. obtusifolius have been described: var. antarcticus Malta, characterized by small plants, leaves and capsules, and leaf cells with strongly thickened walls (Malta, 1924: 334); and var. latifolius Malta, established to accommodate expressions with wider leaves (Malta, 1924: 334). However, all these features are found in typical Z. obtusifolius, which always grows in low turfs, has hyaline to greenish or yellowish-brown leaves (under light microscopy), with cells almost isodiametric, bulging throughout, strongly thick-walled, usually smooth at leaf base but papillose above. Regarding capsule size, a specimen reported by Malta as var. antarcticus was examined, and its capsules are not significantly smaller than those in typical Z. obtusifolius. It became clear that the characters indicated by Malta to segregate the two varieties fall within the variation range of the typical Z. obtusifolius, and therefore they are considered synonyms of it. 474 the bryologist 109(4): 2006 Zygodon obtusifolius shows variation in some sporophytic features. It usually has eight endostomial segments, although there are occasional extra segments. Malta (1926: 164) reported eight segments, and more rarely 16. A fragmentary prostome, as reported by Lewinsky (1990: 123), was not seen. Peristomial ornamentation is also variable. The OPL is reticulate, and the reticulum walls are either smooth or papillose. Exostomial PPL varies from strongly papillose in some specimens to almost smooth in others. Endostomial PPL has weak longitudinal striae, although Lewinsky (1990: 123) reported a smooth PPL. Selected specimens examined (52). Chile. REGIÓN IX: Chile australis in monte Cordillera de la Costa supra Angol, Dusén 845 (S). AUSTRALIA. TASMANIA: Sophia Point, Macquarie Harbour, Moore 26 (H-BR). BRAZIL. MINAS GERAIS: Serra do Itatiaia, Ule 130 (G 027205); SANTA CATARINA: Serra Geral, Ule 22 (G 027204). COLOMBIA. CUNDINAMARCA: San Cayetano, Hda. Portugal, Cleef 6062 (G 313600). MEXICO. DISTRITO FEDERAL: Mexique, macizo [?illeg.], Bescherelle s.n. (G 027238); JALISCO: Slopes of La Ferrerı́a, above Manantlán, Crum 1053 (G 027239). NEPAL [locality not stated]. Gardner s.n. (BM 79684a, G 027202). NEW ZEALAND. NORTH ISLAND: North Auckland District, Leigh Marine Research Station, Fife 7901 (CHR 106607); SOUTH ISLAND: Nelson, Grant NZ 421 (CHR 303269). VENEZUELA. Prope Coloniam Tovar, Fendler 25 (G 027207, G 027213). SUBG. ZYGODON Diagnosis. Plants to (0.2–)0.5–6(15) cm tall, usually in turfs, on bark or rock. Stems erect or prostrate, simple or branched. Leaves lanceolate, rhomboidal-lanceolate or rarely lingulate; apex usually acute; upper laminal cells 6 isodiametric, roundedhexagonal to ovate, not bulging, always papillose; basal leaf cells short to long-rectangular, smooth and differentiated from upper cells, isomorphic or dimorphic. Propagula often present, cylindrical, fusiform, ovoid or clavate, with only transverse septa or with tranverse and longitudinal septa. Dioicous or synoicous, occasionally autoicous. Seta distally dextrorse or sinistrorse, in the basal part sinistrorse, without torsion or exceptionally dextrorse. Peristome double, simple or absent. Spores 10–30 lm in diameter, papillose or foveolate, trilete mark absent or distinct. Sect. Stenomitrium Mitt., J. Linn. Soc. Bot. 12: 238. 1869. Diagnosis. Plants in turfs or loose mats. Stems erect or prostrate. Leaves distinctly 5-ranked, lanceolate to lanceolate-rhomboidal; apex acute to acuminate; basal cells in dimorphic bands of hyaline, thinwalled cells with wide lumina, and yellowish-brown, strongly thick-walled cells, usually nodulose, with narrower lumina. Dioicous. Setae distally sinistrorse, in the basal part without torsion, sinistrorse or dextrorse. Peristome double. Endemic to South America, three species grow in the study area: Zygodon pentastichus, Z. bartramioides and Z. chilensis. 3. Zygodon pentastichus (Mont.) Müll. Hal., Syn. Musc. Frond. 1: 675. 1849; Aulacomnium pentastichum Mont., Ann. Sci. Nat. Bot., III, 4: 103. 1845; Stenomitrium pentastichum (Mont.) Broth., Nat. Pflanzenfam. 1(3): 464. 1902 [1903]; Pentastichella pentasticha (Mont.) Müll. Hal., Oesterr. Bot. Z. 47: 421. 1897. TYPE: ‘‘Chile australis, ubi primus legit Pöppig, dein C. Gay’’ (PC?, not found). Macromitrium poeppiggi Duby, Mém. Soc. Phys. Genève 19: 295, tab. 2, fig. 2. 1868. TYPE: ‘‘In Andibus Antuccensibus Chili repertam a cl. Pöppig, in herbario olim Nees von Esenbeck nunc meo inveni’’. Synonymized by Brotherus (1902–1903: 494). Zygodon uncinatus Mitt., J. Linn. Soc. Bot. 12: 234. 1869; Codonoblepharon uncinatum (Mitt.) A. Jaeger, Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1872–73: 118 (Gen. Sp. Musc. 1: 396). 1874. TYPE: [Chile] ‘‘Ins. Chiloé, Lobb’’ (lectotype, selected here, NY!). Synonymized by Malta (1926: 179). Pentastichella aurea Dusén, Rep. Princeton Univ. Exped. Patagonia, Bot. 8(3): 122. 1903, nom. nud. Pentastichella jaffuelii Thér., Revista Chilena Hist. Nat. 25: 301, tab. 27, fig. 2 a–h. 1921, non Zygodon jaffuelii Thér.; Zygodon porteri Thér. nom. nov., Revista Chilena Hist. Nat. 30: 351. 1926. TYPE: ‘‘Crête des Monts de Las Piedras (Marga Marga), sur l’écorce des vieux quillayes (Jaffuel, févr. 1917), stérile’’ (isotype, FH!), syn. nov. Pentastichella pentasticha var. strictifolia Thér., Revista Chilena Hist. Nat. 28: 131. 1924; Zygodon pentastichus var. strictifolius (Thér.) Malta, Lat- Calabrese: Zygodon in southern South America vijas Univ. Bot. Dārza Darbi 1: 141. 1926. TYPE: ‘‘Temuco (F. Jaffuel)’’ (PC?, not found), syn. nov. Zygodon porteri Thér. var. crispatulus Thér., Revista Chilena Hist. Nat. 30: 351. 1926; Zygodon pentastichus var. crispatulus (Thér.) Malta, Latvijas Univ. Bot. Dārza Darbi 1: 140, fig. 87f. 1926. TYPE: ‘‘I. Chiloé, Ancud (leg. F. Jaffuel, 1924)’’ (isotype, FH!), syn. nov. Illustrations. Figs. 2E–F, 8–9. Description. Plants robust, in lax mats, green above, brown to dark reddish-brown in the prostrate stems and lower parts of branches. Stems prostrateascending, profusely covered by a reddish-brown tomentum, regularly branched, branches erect, to 4 cm high. Rhizoids reddish-brown, smooth. Leaves clearly in 5 ranks, erect, appressed and keeled when dry, occasionally flexuose and slightly crisped above, spreading to recurved from an appressed base when moist, 2.1–3.0 3 0.6–0.9 mm, lanceolate, apex longacuminate; margins plane, entire and smooth at base, entire and papillose above; upper and middle leaf cells isodiametric, hexagonal to rounded, strongly thickwalled, with lumina slightly oval (6–)8–10 lm in diameter, papillose, strongly differentiated from basal cells; papillae (1–)3–4 per cell, simple, low and blunt; basal cells long and narrow, 56–82(90) 3 6–8 lm, smooth, light bands of thin to slightly thick-walled, hyaline, larger cells alternating with yellow bands of strongly thick-walled, porose, yellowish-brown, narrower cells; costa ending below apex, 30–42 lm wide in the lower 1/3, dorsal superficial cells smooth, in section with 2 ventral guide cells and dorsal stereids. Propagula absent. Dioicous. Perichaetial leaves differentiated, erect when moist, 2.3–2.5 3 0.4–0.7 mm, lanceolate, apex acute to acuminate; margins entire; cells elongate, smooth or with few papillae, basal cells not differentiated as in stem leaves. Seta 10–15 mm long, sinistrorse in the distal part, sinistrorse or without torsion at base; capsule erect, oblong to cylindrical, 2.0–2.5 mm long, with 8 longitudinal ribs throughout; exothecial bands differentiated, of 4–5 cell rows each, interrupted by 3–4 smaller cell-rows surrounding capsule mouth; operculum conic at base, with a long beak; peristome double; exostome robust, of 16 teeth, partially paired (al least joined at base), typically recurved, dorsal surface (OPL) with coarse, blunt papillae, densely and uniformly distributed, covering a basal reticulum hardly visible, ventral 475 surface with papillae in thin vertical lines or irregularly and densely covering the lower 2/3, with coarse papillae, sometimes joined in the upper 1/3; endostome of 16 very wide segments, shorter than exostome, fused at base, strongly keeled, dorsally (PPL) smooth or with short, blunt, coarse, disperse papillae, ventrally (IPL) strongly papillose, basal membrane high and continuous. Spores papillose, (17–)20–28 lm in diameter, trilete mark indistinct. Ecology. Usually epiphytic, in lax mats on tree trunks, old stumps and logs, more rarely on rotten wood; often on old Nothofagus, less common on Austrocedrus, Araucaria, Aristotelia, Peumus, Eucryphia, Drymis, Gevuina and Pernettya. It has been also found on rocks, bricks and rarely on soil around trunk bases. Distribution (Fig. 23B). It ranges from Peru to southern Argentina and Chile through the Andes. In Argentina is known from Neuquén, Rı́o Negro and Chubut provinces, and from regions VII, VIII, IX, X and XI in Chile; also reported from the Juan Fernández Islands. Differentiation. Zygodon pentastichus shares some important features with Z. bartramioides and Z. chilensis, like the ovate upper leaf cells, basal cells forming distinct bands and the sinistrorse setae to the apex, suggesting that they are closely related. However, it has leaves loosely clasping the stem at base and more clearly arranged in five rows, prostrate stems with erect branches and lacks propagula. Sporophytically, it can be distinguished by operculum shape (longer than in Z. bartramioides and Z. chilensis), and by the 16 exostome teeth arched and touching the capsule wall only at tips, but not appressed to the capsule wall as in Z. bartramioides and Z. chilensis. Finally, the spores of Z. pentastichus are larger, without trilete mark, and papillose (foveolate in Z. bartramioides and Z. chilensis). Variability. Zygodon pentastichus is very variable in branch length, some of which are robust and to 4 cm, while others only extend 1 cm above the substrate. Leaves vary from very rigid to strongly flexuose, a condition usually related to water availability; plants from more humid places have flexuose, longer leaves narrowed in a long-acuminate apex occasionally crispate when dry, and then not clearly pentastichous. Although the 5-row disposition of the leaves can be sometimes difficult to notice when dry, 476 the bryologist 109(4): 2006 Figure 8. Zygodon pentastichus. A. Habit when dry. B. Habit when moist. C. Leaves. D. Apex. E. Leaf basal cells showing differentiated cell-bands. F. Leaf cross-sections. G. Perichaetial leaf. H. Peristome (inner view). I. Spores. A, B from Calabrese 336 (BCRU); cI from Crosby 12292 (MO); cII from Calabrese 200154 (MA); D–F from Calabrese 4612 (BCRU); G from Calabrese 200159 (MA); H, I from Thaxter 44 (FH). Calabrese: Zygodon in southern South America 477 Figure 9. Zygodon pentastichus. SEM photographs of peristome A. Peristome. B–E. Exostome. B. Details of the basal OPL. C.. OPL, basal and middle portion of teeth. D. PPL, basal. E. PPL, apical. F. Outer surface of endostomial segments (PPL). A, D–F from Calabrese 169 (BCRU); B, C from Santensson 2210 (FH-BARTRAM). it is always very distinct when moist. In contrast, plants from drier places have stiff, erect and appressed leaves in five regular rows when dry. The Chilean specimens from Ancud collected by Jaffuel in 1924 (type of Z. pentastichus var. crispatulus) and from Guaitecas (distributed by Dusén as Pentastichella aurea) have strongly crispate and flexuose leaves when dry, but either gametophytically and sporophytically they are identical to specimens of the typical variety. Although both are identical, the Guaitecas material was considered by Malta (1926: 140) to represent a transition towards var. crispatulus. A similar habit is shown by a collection from MargaMarga (Chile), collected by Jaffuel in 1917 and distributed as Pentastichella jaffuelii Thér. The type material of var. strictifolius, collected by Jaffuel in Temuco, was not available for study. This variety was described on the basis of its erectappressed leaves and shorter setae and capsules. However, dry leaves fall into the leaf variability 478 the bryologist 109(4): 2006 previously discussed, as do seta length and capsule size, which further do not vary significantly in this species. In this treatment the two described varieties of Z. pentastichus are included in the range of variability of the typical expression. Selected specimens examined (298). ARGENTINA. CHUBUT: Lago Menéndez, 1-XII-1940, Kühneman s. n. (BA 5254); NEUQUÉN: Dpto. Los Lagos, picada a Cascada Los Cántaros, Calabrese 169 (BCRU 1810); RIO NEGRO: Dpto. Bariloche, Cerro Llao Llao, Calabrese 475 (BCRU 1811). CHILE. REGIÓN V. VALPARAÍSO: Crete des monts de Las Piedras (Marga Marga), II-1917, Jaffuel s.n. (FH-BARTRAM 12263), JUAN FERNÁNDEZ: Masafuera, en cerro Inocentes, Looser 6310 (MO 3987655); REGIÓN VII. LINARES: Bullileo ca. 50 km east of Parral in the precordillera, near Laguna Amargo, Landrum 1523a (MO 2860320), MAULE: ‘‘Bosque Fisco’’ between Quirihue and Cobquecura, Landrum 1539 (MO 2856136), TALCA: Empedrado, Landrum 6341 (MO 3987654); REGIÓN VIII. Andes Antucenses, Pöppig 33 (G 027208), ARAUCO: ridge south of Cerro Lanalhue, southwest of Lago Lanalhue, Fundo Tranquivora, Crosby 13051 (MO 2521905), CONCEPCIÓN: Concepción, IV-1925, Bertho s.n. (FH); REGIÓN IX. CAUTÍN: Parque Nacional Villarrica, near Refugio Villarrica, 6.1 km by road south of park entrance, Crosby 11802 (MO 2521913), Dpto. Villarrica, Pucón, Hosseus 374 (JE-HERZOG), MALLECO: Reserva Forestal Malleco, Landrum 6340 (MO 3987638), MALLECO/ARAUCO: Araucaria forest in Parque Nacional Nahuelbuta, 10 km west of park entrance and 48 km by road west of Angol, Cordillera Nahuelbuta, Crosby 13069 (MO 2521895); REGIÓN X. CHILOÉ: Isla Chiloé, 5 km by road west of Ancud, Crosby 12335 (MO 2521932), ISLA GUAITECAS: Patagonia occ. in insulis Guaitecas, Dusén 670 (FH, JE), LLANQUIHUE: Laguna Verde, Mahu & Tapia 24343 (MO 3987720), OSORNO: Yerbas Buenas, centro de recreación Las Cascadas, Mahu 21359 (MO 3987726), VALDIVIA: Valdivia, Hofmann 21 (HBG); REGIÓN XI. AISÉN: Puerto Chacabuco 6IV-1967, Seki s.n. (HIRO 1894-a). PERU. YUNGAY: Dpto. Ancash, an der Laguna Llanganuco, 17-X-1973, Hegewald 7576 (MO 3670879). 4. Zygodon bartramioides Dusén ex Malta, Latvijas Univ. Raksti 10: 320.1924; Pentastichella bartramioides Dusén, nom. nud. in sched.; Zygodon cylindropyxis Müll. Hal. ex Malta, Latvijas Univ. Raksti 10: 320. 1924, nom. inval. pro synon.; Zygodon robustulus Broth. ex Malta, Latvijas Univ. Raksti 10: 320. 1924, nom. inval. pro synon. TYPE: ‘‘Chile: o. n. O. [locality not indicated] (Philippi, Musci frondosi N8 13); o. n. O. (Pöppig); Angol (Dusén) als Z. robustulus Broth.; Anden von Villarica (Neger)’’. TYPE: Chile australis in monte Cordillera de la Costa, supra Angol oppidam in truncis Araucariae imbricatae, 5-XI-1896, Dusén 362 (lectotype, here designated, FH-BARTRAM!, isolectotypes, FH-BARTRAM!, S-B6278!, S-B6279!, S-B6280!; syntype, ‘‘Neger’’, JE-HERZOG!). Pentastichella robustula Dusén ex Paris, Index Bryol. 4: 320. 1905, nom. nud. Stenomitrium robustulum Dusén ex Paris, Index Bryol. 4: 320. 1905, nom. nud. Zygodon robustus Broth. in Malta, Latvijas Univ. Bot. Dārza Darbi 1: 79. 1926, nom. nud. in syn. Zygodon tristis Herzog, Rev. Bryol. Lichenól. 29: 196. 1960. TYPE: ‘‘Südchile: Hacienda Freire, an Eucalyptus, G. H. Schwabe, n8 7’’ (holotype, JEHERZOG!), syn. nov. Illustrations. Figs. 2D, 3F, 10–11. Description. Plants robust, 2(4) cm tall, in dense turfs, green above, brown below. Stems erect, branched. Rhizoids reddish-brown, usually roughened, extending up the stems and partially covering them in lower 1/3. Leaves appressed and strongly keeled when dry, erect when moist, (0.7–)0.9–1.7 3 0.2–0.4 mm at base and (0.3–)0.4–0.8 mm wide at shoulders, lanceolate-rhomboidal, decurrent, apex acute; margins plane, entire at base, slightly papillose above, sometimes lightly denticulate towards apex, upper leaf cells rounded-hexagonal, isodiametric, thick-walled, with lumina slightly oval, (6–)8– 12(14) lm in diameter, papillose; papillae (1–)2–4 per cell, usually simple, some branched, to 4 lm high, blunt; basal cells elongate rectangular to shortly rectangular, 20–74(90) 3 (3–)6–13(18) lm, smooth, occasionally with only a blunt papilla, in light bands of cells with hyaline thin walls alternating with yellow bands of cells with thickened and colored walls, sometimes nodulose (especially in older leaves), suddenly and clearly differentiated from upper cells; marginal cells shortly rectangular to sub-quadrate; costa ending below the apex, (25–)29–43(48) lm wide in lower 1/3, in a deep furrow from base to Calabrese: Zygodon in southern South America 479 Figure 10. Zygodon bartramioides. A, C. Habit when dry. B. Habit when moist. D. Wet capsule. E. Leaves. F. Perichaetial leaf. G. Apex. H. Leaf basal cells. I. Leaf cross-sections. J. Propagula. K. Peristome (inner view). L. Spores. A from Schwabe 81 (JE); B, G, iII, jIII from Schwabe 7 (JE); C, D, K, L from Neger 45 (S); eII, H, iI, jI from Dusén 362 (S); eI, F from Schwabe 61 (JE); iIII from Hosseus 393 (JE). 480 the bryologist 109(4): 2006 Figure 11. Zygodon bartramioides. SEM photographs of peristome. A. Capsule mouth and peristome in lateral view. B–E. Exostome: B. Details of the basal OPL. C. OPL, apical. D. PPL, middle portion of teeth. E. PPL, apical. F. Outer surface (PPL) of the endostomial segments. A–F from Dusén 362 (FH). upper 4/5, flattened with the lamina above, dorsal side papillose, in section with 2 ventral guide cells and dorsal stereids. Propagula in brownish-yellow axillary stalks, cylindrical or clavate, hyaline, 40–67 3 15–23 lm, (3–)4(5)-celled, with only transverse septa. Dioicous. Perichaetial leaves differentiated, erect when moist, 1.4–1.7 3 0.28–0.32 mm, narrowly lanceolate, apex acute; margins entire, partially involute; cells elongate, smooth or with scattered papillae, undifferentiated at base. Seta 2–5 mm long, sinistrorse in the distal part, sinistrorse or without torsion at base; capsule erect, ovoid to ellipsoidal, ca 1.2 mm long, with 8 longitudinal ribs except at base which is slightly sulcate to almost smooth; exothecial bands differentiated, of 4 cell rows each, interrupted by a continuous ring of 2–4 smaller cells surrounding capsule mouth; operculum conical at base, shortly rostrate; peristome double; exostome robust, of 8 pairs of teeth, teeth lacunose, partially splitting along the middle line, recurved and appressed to the capsule when dry, dorsal surface (OPL) with very coarse, blunt papillae disposed on the edge of lamellae that Calabrese: Zygodon in southern South America form a reticulum in the lower 1/3–2/3, simple papillae or sometimes coarse lines vertically oriented formed by the fusion of papillae in the upper 1/3 of the tooth, ventral surface (PPL) roughened at base, densely papillose in the upper 2/3; endostome of 8 segments, dorsal surface (PPL) smooth, ventral surface (IPL) striate and with papillae vertically and radially disposed in the lower 2/3, distally with coarse papillae, basal membrane low, continuous and striate. Spores foveolate (with numerous depressions or cavities), 10–12 lm in diameter, trilete mark distinct. Ecology. A typically epiphytic species. Although data on phorophytes are scarce, it has been found on Araucaria sp., Nothofagus obliqua (Mirb.) Oerst. and Eucalyptus sp. Distribution (Fig. 24A). Zygodon bartramioides is a Chilean endemic known from Región IX and Región X (Malleco, Cautı́n, Valdivia and Osorno provinces). Differentiation. Zygodon bartramioides could be confused with the closely related Z. chilensis, especially on the basis of peristome characters. However, there is a set of features, particularly gametophytic, that separates both taxa: propagule size, color and morphology, leaf shape and basal areolation, and seta length. The propagula are the best distinguishing character, especially because they are abundant in both species. Zygodon bartramioides has hyaline, smaller propagula with only transverse septa, while Z. chilensis has larger, brownish propagula occasionally branched, often with longitudinal as well as transverse septa. Leaves shape is another differentiating character: Z. bartramioides has lanceolate-rhomboidal leaves whereas they are lanceolate to narrowly lanceolate in Z. chilensis. Basal cells are usually more shortly rectangular and nodulose in Z. chilensis than in Z. bartramioides. Finally, setae are 2–5 mm long in Z. bartramioides, but longer, to 10 mm long, in Z. chilensis. Variability. The studied collections vary both in shape and size of the papillae of the upper laminal cells. Some cells have low and simple papillae, whereas in other cells of the same leaf they are branched. Moreover, papillae can be variably tall or short in different leaves of the same specimen, and also vary in number, from the common 2–3 to 4. The apices of older leaves are usually eroded, as are the apical cells, and thus it is not possible to distinguish papillae. Zygodon tristis Herzog was described from a sole 481 collection from Hacienda Freire (Schwabe 7), growing on cultivated Eucalyptus. This is a very poor specimen that surely represents a young, under-developed specimen. It has fewer rhizoids, less papillose leaves with simple papillae (only a few branched), and a costa slightly papillose dorsally. The examination of the type of Z. tristis indicates it is a synonym of Z. bartramioides. Typification. Of the specimens reported by Malta (1926: 117), the best collection is Dusén 362, which was moreover widely distributed to several herbaria. The specimens kept at S (where the Dusén herbarium is housed) are sterile, while the material in FH (two specimens) has sporophytes. The other collection reported by Malta (Villarrica, Neger, JE!) is large and fertile, but infected by fungi and there are not duplicates in the consulted herbaria. Dusén 362 (FH 9678-HERB. FLEISCHER!) is therefore designated as lectotype. Selected specimens examined (13). CHILE. REGIÓN IX. CAUTÍN: Dept. Villarrica: Pucón, Hosseus 393 (JEHERZOG), MALLECO: Chile australis in monte Cordillera de la Costa, supra Angol oppidam in truncis Araucariae imbricatae, Dusén 362 (FH, S-B62769, SB6278, S-B6280); REGIÓN X. OSORNO: Termas de Puyehue, Schwabe 61 (JE-HERZOG), VALDIVIA: Valdivia, Neger 45 (S). 5. Zygodon chilensis Calabrese & F. Lara, J. Bryol. 28: 97. 2006. TYPE: CHILE. VALDIVIA: Bima District, Cordillera de Alerce, on bark of Fitzroya patagonica (alerce), 650 m, 13-II-1958, Eyerdam 11000 (holotype, UC 271784!; isotypes, H!, NY!). Illustrations. Figs. 1D, 12–13. Description. Plants robust, 2(5) cm tall, in dense turfs, green or yellowish-green above and brown below. Stems erect, frequently branched. Rhizoids reddish-brown, roughened to papillose, abundant at base of stems. Leaves appressed when dry, erect-patent when moist, (1.1–)1.4–1.9 3 0.2– 0.4(0.6) mm, lanceolate to narrowly lanceolate, keeled, decurrent, with acute apex; margins plane, entire and smooth at base, papillose above, usually with 1 or few teeth at the apex; upper leaf cells rounded-hexagonal, with lumina slightly oval, thickwalled, (9–)11–15 lm in diameter, papillose; papillae (1–)2–4 per cell, simple, blunt to subacute, rarely acute; basal cells elongate-rectangular or shortrectangular, (14–)21–40(54) 3 (6–)9–15 lm, 482 the bryologist 109(4): 2006 Figure 12. Zygodon chilensis. A. Habit when dry . B. Habit when moist. C. Leaves. D. Perichaetial leaf. E. Leaf apex. F. Leaf basal cells. G. Leaf cross-section . H. Propagula. I. Peristome and spores. A, B, D, I from Eyerdam 11000 (UC); C from Eyerdam 10999-a (UC); E from Seki s.n. (HIRO 750-a); F from Eyerdam 1564-b (UC); G, hI from Eyerdam 11019-a (UC); hII from Seki s.n. (HIRO 545-c). Calabrese: Zygodon in southern South America 483 Figure 13. Zygodon chilensis. SEM photographs of peristome. A. Lateral view of the capsule mouth and peristome. B–E. Exostome. B. Details of the apical OPL. C. PPL, inner surface of the tooth and basal outer surface of the endostomial segments. D. PPL, middle portion of teeth. E. PPL, apical. F, G. Endostome. F. IPL, basal. G. PPL and IPL, apical. H. Spores. A–H from Eyerdam 11000 (H). 484 the bryologist 109(4): 2006 smooth, in light bands of cells with hyaline thin walls alternating with yellow bands of cells with thickened, nodulose and colored walls; marginal basal cells subquadrate or rectangular, 9–21 3 9–10 lm wide; costa ending below the apex, 33–54 lm wide in lower 1/3, in a deep furrow in the basal 4/5 and in the same plane with the lamina above, dorsally papillose in the upper 2/3, in section with 2 ventral guide-cells and dorsal stereids. Propagula cylindrical or clavate, usually brown, (75–)87–120 3 (21–)24–30 lm wide, 4–9-celled, sometimes branched and then to 16-celled, with transverse septa, but frequently also with longitudinal septa in one or both extremes, conspicuous due to size and color, as well as the usual abundance, occasionally remaining attached on the leaf surface. Dioicous. Perichaetial leaves differentiated, erect when moist, 1.90–2.10 3 0.28–0.32 mm, narrowly lanceolate, apex acute-acuminate; margins entire, 6 involute; cells elongate, smooth or with scattered papillae, basal cells undifferentiated. Seta 7– 10 mm long, sinistrorse in the distal part, dextrorse at base; capsule erect, cylindrical to ellipsoidal, 1.5–2.0 mm long, with 8 longitudinal ribs; exothecial bands differentiated, of 4 cell rows each, interrupted by a continuous ring of 3–4 almost isodiametric cells around capsule mouth; operculum conical at base, shortly rostrate; peristome double; exostome robust, of 8 pairs of teeth, each tooth lacunose, partially splitting along the middle line except at base, recurved and appressed to the capsule when dry, dorsal surface (OPL) with coarse papillae on the edge of lamellae forming a reticulum in the lower tooth half, papillae and lines (formed by the fusion of papillae) vertically oriented in the upper tooth part, ventral surface (PPL) usually almost smooth or roughened at base, sometimes with papillae longitudinally aligned or with longitudinal smooth lines at the lower part, the upper 1/2–2/3 densely papillose; endostome of 8 hyaline segments, occasionally with some (1–8) less developed intercalary segments, dorsal surface (PPL) keeled, completely smooth or slightly striate at base, ventral surface (IPL) clearly striate with some scattered papillae at base, that become gradually aligned in the upper half, coarsely papillose towards apex, basal membrane low, continuous and striate. Spores foveolate, 10–12 lm in diameter, trilete mark distinct. Ecology. Zygodon chilensis grows on Nothofagus antarctica (G. Forst.) Oerst., Fitzroya and Podocarpus, from sea level to 900 m. Distribution (Fig. 23D). Zygodon chilensis, so far endemic from Chile, is only known from two population groups in Valdivia (Región X) and Aisén (Región XI). Differentiation. Zygodon chilensis is closely related to Z. bartramioides. Both taxa have distally sinistrorse setae, double peristomes, foveolate, small spores with trilete markings, and basal leaf cells differentiated in longitudinal bands. However, Z. bartramioides has lanceolate-rhomboidal leaves with distinct shoulders, basal leaf cells sharply differentiated from upper cells, blunt and sometimes branched papillae, smaller propagula and shorter (to 5 mm) setae. Variability. This species grows in two different population groups in the study area, which differ in leaf shape and areolation, and propagule size and color (Calabrese et al. 2006). Southern specimens have more narrowly lanceolate leaves with short-rectangular basal cells scarcely differentiated from upper cells, and propagula usually larger, (75–)105–120 3 (21–)24–30 lm, with 4–9(16) cells, always with colored walls and more often branched. Selected specimens examined (7). CHILE. REGIÓN X. VALDIVIA: Bima District, Eyerdam 10999a (UC 271783, paratype); REGIÓN XI. AISÉN: Estancia Rı́o Romero, cerro junto al Ventisquero Nef, 19/20-III1967, Seki s.n. (HIRO 1564-b, paratype). Sect. Zygodon Zygodon sect. Euzygodon Müll. Hal., Syn. Musc. Frond. 1: 671. 1849, nom. illeg. Diagnosis. Plants in turfs. Stems erect. Leaves distinctly 5-ranked or not, lanceolate or, exceptionally, lingulate; apex acute or rarely rounded-obtuse; basal leaf cells isomorphic. Dioicous or synoicous, rarely autoicous. Setae distally dextrorse, sinistrorse in the lower part. Peristome double, simple or absent. Widespread in both hemispheres, there are seven species and one variety in the study area: Zygodon intermedius, Z. pichinchensis, Z. reinwardtii var. reinwardtii, Z. hookeri var. hookeri, Z. hookeri var. leptobolax, Z. jaffuelii, Z. papillatus and Z. magellanicus, the last three endemic to southern South America. 6. Zygodon magellanicus Dusén ex Malta, Latvijas Univ. Bot. Dārza Darbi 1: 173. 1926. TYPE: ‘‘Hab. Calabrese: Zygodon in southern South America 485 Figure 14. Zygodon magellanicus. A. Habit when dry. B. Habit when moist. C. Leaves. D. Leaf apex. E. Cells in middle portion of leaf. F. Leaf basal cells. G. Leaf cross-section. H. Propagula. A, B, cIII, E, hI from Dusén 83 (S); D, F, G, hII from Schiavone & Ochyra CM 6668 (BA); cI, hIII from Matteri & Schiavone CM 2449 (BA); cII from Matteri, Schiavone & Piñeiro CM 5757 (BA). Chile australis’’. TYPE: ‘‘[Chile:] Patagonia, Punta Arenas in saxis, P. Dusén N8 83, 27-XI-1895’’ (lectotype, selected by Calabrese et al. 2002, SB6273!; isolectotypes, H!, S-B6274!, S-B6275!). Zygodon gracillimus Dusén, Rep. Princeton Univ. Exped. Patagonia, Bot. 8(3): 122. 1903, p. p., nom. nud. (Some specimens are Z. magellanicus while others are Z. papillatus.) Illustrations. Figs. 1B, 2D, 14. Description. Plants robust, (0.7–)1.6–2.5 cm tall, in lax turfs, green above, brown below. Stems erect, simple or scarcely branched. Rhizoids reddish-brown, papillose, extending up the stem and partially covering its lower part. Leaves erect and keeled when dry, patent when moist, (0.7–)0.96–1.75 3 (0.22–)0.32– 0.45 mm, lanceolate, narrower towards base, decurrent, with acute apex; margins plane, entire at base, papillose above; upper leaf cells rounded-hexagonal, 486 the bryologist 109(4): 2006 thick-walled, 8–13 lm in diameter, slightly smaller to the margins, papillose; papillae 3–5(6) per cell (usually 4), simple, blunt to subacute; basal cells quadrate to short-rectangular towards the margins, 9– 12 lm, rectangular towards the costa, 12–45 3 6–15 lm, smooth; costa ending below the apex, 36–51 lm wide in lower 1/3, in a deep furrow, superficial cells elongate on both sides, dorsally smooth, ventrally covered by papillose laminal cells towards the apex, in section with 2 ventral guide cells and dorsal stereids. Propagula in brownish-yellow axillary stalks, clavate, reddish-brown, 50–90 3 30–39 lm, 5–12-celled, with transverse and longitudinal septa. Dioicous. Sporophytes unknown. Ecology. Zygodon magellanicus usually grows on rock and rock crevices, and only once was found on bark of Nothofagus pumilio (Poepp. & Endl.) Reiche. Distribution (Fig. 23B). An Andean-Patagonian and Fuegian endemic known from Neuquén and Tierra del Fuego in Argentina and from Región XI and Región XII of Chile. Differentiation. This taxon is closely related to Z. papillatus, which however has smaller (19–32 3 17–25 lm), mostly ovoid and yellowish-brown propagula, branched papillae and slightly thickened laminal cell walls, smooth or slightly roughened rhizoids, and forms slender, more compact turfs. From the remaining species in the area Z. magellanicus can be distinguished by having brown propagula with longitudinal as well as transverse walls. Variability. Zygodon magellanicus scarcely varies, with only the leaves ranging from small and broadly lanceolate to long and narrowly lanceolate. The variability of this taxon, as well as its differentiation from Z. papillatus, has been already described in length by Calabrese et al. (2002). Selected specimens examined (14). ARGENTINA. NEUQUÉN: Villa La Angostura, Inacayal, Schiavone & Matteri CM 4725 (BA, BCRU); TIERRA DEL FUEGO: Patagonia australis in territorio Rı́o Chico, Hatcher s.n. (S-B6277); USHUAIA: Arroyo Grande (5 km. NE de Ushuaia), Siete Cascadas, Matteri & Schiavone CM 2449 (S). CHILE. REGIÓN XI. AISEN: estancia Rı́o Romero, cerro junto al Ventisquero Nef, 19/20-III-1967, Seki s.n. (HIRO 1456-c); REGIÓN XII: Penı́nsula Brunswick, Puerto Isidor, Roivainen 2405 (FH), Fuegia Media, Lago Blanco, Roivainen 180 (FH-BARTRAM). 7. Zygodon papillatus Mont., Ann. Sci. Nat. Bot., III, 4: 106. 1845; Codonoblepharon papillatum (Mont.) A. Jaeger, Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1872–73: 118 (Gen. Sp. Musc. 1: 396). 1874; Z. papillosus Mont. ex Broth. in Engler & Prantl, Nat. Pflanzenfam. 1(3): 462. 1902 [1903], nom. inval., orthogr. err. TYPE: ‘‘Hab. ad corticem arborum Chiles australioris invenit hunc muscum cl. C. Gay. Herb. Mus. Par.’’ (lectotype, selected by Calabrese et al. (2002), PC-MONTAGNE!). Zygodon gracillimus Dusén, Rep. Princeton Univ. Exped. Patagonia, Bot. 8(3): 122. 1903, p. p., nom. nud. (Some specimens are Z. magellanicus while others are Z. papillatus.) Illustrations. Figs. 1A, 3C, 15. Description. Plants slender, (0.4–)2.0–4.5 cm tall, in compact turfs, light green above, brown below. Stems erect, simple or scarcely branched. Rhizoids reddish-brown to yellowish, smooth to slightly roughened, ascending up the stems. Leaves erect when dry, erect-patent when moist, 0.66–0.85 3 0.14–0.30 mm, lanceolate, narrower towards the base, 6 decurrent, with acute apex; margins plane, entire and smooth at base, papillose above; upper leaf cells hexagonal, slightly thick-walled, 9–14 lm in diameter, coarsely papillose; papillae (3–)4–6(9) per cell, generally branched, blunt; basal cells short-rectangular, 9–32 3 6–13 lm, smooth; costa ending below the apex, 28–30 lm wide in the lower 1/3, in a deep furrow, superficial cells elongate on both surfaces, dorsally smooth in the lower 2/3, papillose in the upper 1/3, in section with 2 ventral guide-cells and dorsal stereids. Propagula ovoid to clavate, yellowish brown, 19–32 3 17–25 lm, with transverse and longitudinal septa, although sometimes with only transverse ones. Dioicous. Perichaetial leaves undifferentiated. Seta 4 mm long, dextrorse in the distal part, sinistrorse at base; capsule erect, obovate, ovoid to pyriform, 0.8–1.1 mm long, with 8 longitudinal ribs; exothecial bands differentiated, of 4–5 cell rows each; operculum conical at base, shortly rostrate; peristome rudimentary, of 8 endostome hyaline segments, dorsal and ventral (PPL and IPL) surfaces smooth, basal membrane low, continuous and smooth. Spores minutely papillose, 12–15 lm in diameter, trilete mark distinct. Ecology. This species has been only found on bark. Reported phorophytes are Nothofagus betuloides (Mirb.) Oerst., N. pumilio and Podocarpus sp. Calabrese: Zygodon in southern South America 487 Figure 15. Zygodon papillatus. A. Habit when dry. B. Habit when moist. C. Leaves. D. Leaf apex. E. Cells in middle portion of leaf. F. Leaf basal cells. G. Leaf cross-section. H. Propagula. I. Capsule when dry. J. Peristome and spores. A, B, cI, D–F, H–J from Gay s.n. (PC); cII, G from Chile (PC); cIII from Dusén II-1897 (S). Distribution (Fig. 23C). Zygodon papillatus is known only from Rı́o Negro in Argentina and from regions VIII, IX, X, XI and XII of Chile. Differentiation. This taxon is closely related to Z. magellanicus, which however has larger (50–90 3 30– 39 lm), clavate and reddish-brown propagula, leaf cells with simple papillae (some branched papillae may occur very rarely) and very thick walls, papillose rhizoids, and forms robust, loose turfs. Possible confusion between Z. papillatus and Z. hookeri var. leptobolax, both with similar peristomes, is unlikely considering sexual condition (dioicous in Z. papillatus vs. synoicous in Z. hookeri var. leptobolax), propagula (ovoid to clavate, with longitudinal and transverse septa, yellowish-brown in Z. papillatus vs. fusiform, only with transverse septa, usually hyaline or green- 488 the bryologist 109(4): 2006 ish-hyaline in Z. hookeri var. leptobolax), and the simple papillae and spores larger than 20 lm of Z. hookeri var. leptobolax. Variability. As for Z. magellanicus, the variability and differentiation of Z. papillatus was treated in detail by Calabrese et al. (2002). In any case, Z. papillatus is morphologically very stable. Selected specimens examined (30). ARGENTINA. RÍO NEGRO. BARILOCHE: Reserva Municipal Llao Llao, Cerro Llao Llao, Calabrese 461 (MA). CHILE. REGIÓN IX: Chile australis, Cordillera de la Costa supra Angol, 5XI-1896, Dusén s.n. (S); REGIÓN X: Lago Pillaifa, Schwabe 20 (JE); REGIÓN XI: in valle fluminis Aysén, Dusén 565 (S, JE, FH-BARTRAM). 8. Zygodon pichinchensis (Taylor) Mitt., Hooker’s J. Bot. Kew Gard. Misc. 3: 356. 1851; Didymodon pichinchensis Taylor, London J. Bot. 7: 280. 1848. TYPE: ‘‘Hab. Andes Quitenses, in montibus Pichincha et Chimborazo, Jameson’’ (lectotype, ‘‘Pichincha, Jameson,’’ selected here, BM!; isolectotype, G!). Zygodon setulosus Mitt., J. Linn. Soc. Bot. 12: 237. 1869. TYPE: ‘‘Andes Novo-Granatenses, Weir 334’’ (holotype, NY?, not found). Synonymized by Churchill et al. (2000: 93). Zygodon hystrix Dusén ex Paris, Index Bryol., ed. 2, 5: 139, 1906, nom. nud. ORIGINAL MATERIAL: NY! Leptodontium spinosum R. S. Williams, The Bryologist 33: 73. 1930 [1931]. TYPE: ‘‘Dept. Santander, Paramo de Santurban near Vetas, Colombia, 3950–4160 meters alt. Killip & Smith 17530, Jan. 17, 1927’’. Synonymized by Zander (1972: 278). Triquetrella spiculosa Thér., Rev. Bryol. Lichénol. 9: 14. 1936. TYPE: ‘‘Ecuador, rochers du Condorguachana, Benoist 3150’’ (lectotype, PC, not seen). Synonymized by Churchill et al. (2000: 182). Illustrations. Figs. 1C, 16. Description. Plants robust, (2–)5–7(11) cm, in lax turfs, yellowish-green to brownish-green above, reddish-brown and tomentose below. Stems erect, simple or branched. Rhizoids reddish-brown, smooth or slightly roughened, extending up the stem almost to the apex, profuse in leaves axils. Leaves clearly in 5 ranks, erect and keeled when dry, squarrose-recurved when moist, 1.10–1.78 3 0.37–0.67 mm, ovallanceolate, rapidly narrowed in the upper 1/3, decurrent, apex acute, sometimes ended in a long hyaline apiculus; margins plane, irregularly spinose by large papillae; upper leaf cells rounded to subquadrate, isodiametric, thick-walled, 7–11 lm in diameter, papillose; papillae 1–2(3) per cell, simple or branched, sometimes forked at some height from base, acute to subacute, to 14 lm tall, occasionally sharply pointed and hyaline, often fragile and once broken appearing blunt, frequently longer and spinose at margins and sometimes also at dorsal portion of the costa, reaching 30 lm long; basal cells hardly differentiated from upper cells, short-rectangular, 9– 19 3 5–7 lm, smooth or with 1–2 papillae towards the margins, gradually longer, rectangular, 15–39 3 7–12 lm, smooth or with 1 small papilla towards the costa; costa ending below the apex, red-brown, 36–60 lm wide in lower 1/3, in a deep furrow, dorsally spinosepapillose, in section with two ventral cells and dorsal stereids towards the base and cells 6 homogeneous towards the apex. Propagula absent. Dioicous. Perichaetial leaves differentiated, spreading when moist, 1.78–2.33 3 0.43–0.45 mm, linear-lanceolate, apex acute; margins entire towards base and denticulate towards apex; cells in the upper 1/3 with 1–2 small papillae; median cells smooth or papillose; basal cells smooth, sometimes nodulose, elongate, 30–50 3 6–8 lm. Seta 7–12 mm long, dextrorse distally, sinistrorse at base; capsule erect, cylindrical to cylindric-ellipsoidal, ca 2 mm long, with 8 longitudinal ribs throughout; exothecial bands of 5–8 cell rows each; operculum conical at base, subulate; peristome simple, exostome absent; endostome of 8 hyaline segments, dorsally keeled in the middle line, dorsal and ventral (PPL and IPL) surfaces smooth, basal membrane low, continuous and smooth. Spores finely papillose, 15–17 lm in diameter, trilete mark absent. Ecology. Zygodon pichinchensis usually grows on crags, cliffs and rock crevices, and also on bark and soil under shrubs. According to Churchill et al. (2000) it ranges from 200 to 4800 m. Reported phorophytes are Nothofagus dombeyi (Mirb.) Oerst. and Diplostephium rhomboidale Cuatrec. In the study area it grows on wet places in Nothofagus forests. Distribution (Fig. 24A). In South America, Z. pichinchensis grows along the Cordillera de los Andes from Colombia to Tierra del Fuego, avoiding the more arid areas. It is also known from Central Calabrese: Zygodon in southern South America 489 Figure 16. Zygodon pichinchensis. A. Habit when dry. B. Habit when moist. C. Leaves. D. Perichaetial leaf. E. Leaf apex. F. Cells in middle leaf and margins. G. Leaf cross-section. H. Leaf marginal papillae. I. Papillae in dorsal portion of costa. J. Capsule when dry. K. Peristome and spores. A, B, J from Matteri & Schiavone CM 5133 (BA); cI from Matteri & al. CM 6144 (BA); cII, hII from Jameson s.n. (BM); cIII from Cleef 5663 (G); D, hIII, iI from Cleef s.n. (G 150899); E from Matteri & Schiavone CM 4778-a (BA); F, G, hI from Schiavone & Matteri CM 4519 (BA); kI from Cleef 9819 (G); kII from Cleef 8898 (G); hIV from Cleef 8603 (G); hV, iII from Matteri & Schiavone CM 5103 (BA). 490 the bryologist 109(4): 2006 America and Mexico. In the study area it grows in Chubut and Santa Cruz provinces of Argentina and Chilean Región XI and Región XII. Differentiation. The characteristic leaf cell papillae, as well as the lack of propagula, simple peristome and dioicous sexual condition make confusion of Z. pichinchensis with any other taxon unlikely. Variability. Papillae vary in shape and size (Figs. 1C, 16H–I). In some specimens they are acute and end in an easily broken hyaline tip, thus giving them a blunt appearance, especially in the dorsal portion of the costa; these papillae with hyaline tips are frequently forked. In others specimens they are very large and subacute, with the tip neither hyaline nor fragile. Finally, in the same leaf it is possible to find branched as well as simple papillae intermingled. Papillae also vary in size, even in the same leaf, although they are usually very large (more than 10 lm long) and spinulose or spinose; only exceptionally they are smaller and less distinct. Plant size is also variable, often depending on substrate: plants growing on soil are larger and more robust, to 11 cm high, whereas those on rock or bark are the smallest specimens, just 5–7 cm high. Finally, seta length is also somewhat variable, from 7 to 12 mm, althought there is no correlation with other character variation. Zygodon setulosus was considered a synonym of Z. pichinchensis by Churchill et al. (2000: 93), although previously Churchill and Linares (1995: 621) stated ‘‘according to Griffin III (pers. comm.) these two species could be synonyms.’’ In neither of these works nor in the present study could the type (‘‘Andes Novo-Granatenses,’’ Weir 334) be found. Nevertheless, I studied the other specimen reported by Malta (1926), who was able to compare it with the actual type. This specimen (Apollinaire 371, PC!), as well as all others previously identified as Z. setulosus, belongs to Z. pichinchensis. According to the original description (Mitten 1869), Z. setulosus has shorter setae, cylindrical capsules and narrower leaves, while Z. pichinchensis has elongate setae, oblong-elliptical capsules and wider leaves. As I have already pointed out, seta length is highly variable and cannot be considered as diagnostic. Regarding capsule shape, they are always 6 cylindrical or cylindrical-ellipsoidal, and leaf width varies enough in the same specimen (0.37–0.67 mm) not to be considered of taxonomic importance. I concur with Churchill et al. (2000) that Z. setulosus and Z. pichinchensis are conspecific. Selected specimens examined (96). ARGENTINA. CHUBUT: Parque Nacional Los Alerces, arroyo Las Cascadas, Matteri et al. CM 6144 (BA, BCRU); SANTA CRUZ: southernmost end of Lago Argentino, Cantino M-26 (BA, S, H). CHILE. REGIÓN XI. AISÉN: Estancia Lago Plomo, Ventisquero Soler, 17/20-III-1967, Seki s.n. (HIRO 1849); REGIÓN XII: Patagonia australis, in monte Cordillera de los Andes ad Lago Dickson, 20-XII1896, Dusén s.n. (S). BOLIVIA. LA PAZ. PROV. INQUISIVI: Cumbre Sayaquira, headwaters of Rio Sayaquira, ca. 2.5 km S of Estancia Huaña Hkota, Lewis 87–337 (H); PROV. MURILLO: upper Rı́o Chuquiaguillo, ca. 15–19 km NE of Plaza San Francisco, Lewis 88–430 (G 322940); PROV. SUR YUNGAS: ‘‘Taquesi West’’, West side of Taquesi Pass along Inca Trail to Abra, Lewis 83–2135A-b (MA). COLOMBIA. ARAUCA: Cabeceras de la Quebrada El Playón, Patio Bolos, 2 km al ENE del Alto Curisı́, Cleef 8898 (G 313543); BOYACÁ: Macizo alto N de Belén (Mnpio. Tutasá), Cerro Pan d’Azucar y vecindades, lado SE del Cerro, Cleef 9819 (G 313542). ECUADOR. PICHINCHA: Bell 383 (G 027219); QUITO: Volcán Cayambe, Balazs 81–09/ A (G 242149). VENEZUELA. MÉRIDA: Rangel, Cordillera de los Andes, Sierra de Santo Domingo, páramo de Mucubajı́, just above the Laguna de Los Patos, Griffin, III et al. 017518 (MA 22496). 9. Zygodon intermedius Bruch & Schimp., Bryol. Europ. 3: 41 (fasc. 4, monogr. 9). 1838. TYPE: ‘‘Exemplaria Hookeriana, ex insula Novae-Zelandiae missa, cel. Mougeot et Montagne nobiscum benevole communicavere’’ (lectotype, ‘‘New Zealand, Dusky Sound, A. Menzies,’’ designated by Lewinsky, 1990, BM!) Zygodon conoideus (Dicks.) Hook. & Taylor var. elongatus Hook. & Grev., Edinburgh J. Sci. 1: 132. 1824. TYPE: ‘‘New Zealand; first discovered there by A. Menzies, Esq. Van Dieman’s Land, Dr. Spence and Mr. R. Neill’’ (lectotype, ‘‘New Zealand, leg. Menzies,’’ designated by Lewinsky, 1990, BM!). Synonymized by Lewinsky (1990: 131). Zygodon brownii Schwägr., Sp. Musc. Frond., Suppl. 4: 317b. 1842. TYPE: ‘‘Adhaerentem ad Leskeam sciuroidem Hook. in Terra van Diemen a cl. Brownio lectum vidi’’ (holotype, G, not seen). Synonymized by Malta (1926: 75). Calabrese: Zygodon in southern South America Zygodon angustifolius Hook. & Grev. ex Wilson, London J. Bot. 5: 449. 1846, nom. nud. Zygodon brachyodus Müll. Hal. & Hampe, Linnaea 28: 210. 1856. TYPE: ‘‘Australia, Victoria, Sealers Cove, F. von Müller’’ (isotypes, BM, H, not seen). Synonymized by Malta (1926: 75). Zygodon affinis Dozy & Molk. ex Bosch. & Sande Lac., Bryol. Jav. 1: 107, t. 85. 1859. TYPE: ‘‘Habitat insulam Javae; in summo monte Pangerango Teysmann in herb. Dz. et Mb.’’. Synonymized by Fleischer (1904: 394). Zygodon krausei Lorentz, Moosstudien 162. 1864. TYPE: CHILE. ‘‘Prope Valdiviam, Dr. Krause’’ (lectotype, selected here, S-B6276!; isolectotype, NY!). Synonymized by Malta (1926: 75). Zygodon confertus Müll. Hal., Hedwigia 37: 134. 1898. TYPE: ‘‘Australia, Victoria, F. Campbell’’ (lectotype, selected by Lewinsky (1990), H, not seen). Synonymized by Malta (1926: 75). Zygodon gracilicaulis Müll. Hal., Hedwigia 37: 135. 1898. TYPE: ‘‘New Zealand, near Greymouth, R. Helms’’ (lectotype, selected by Lewinsky (1990), H, not seen). Synonymized by Malta (1926: 75). Zygodon hymenodontioides Müll. Hal., Hedwigia 37: 135. 1898, nom. illeg., non Müll. Hal. 1869 [¼ Anoectangium hymenodontoides (Müll. Hal.) A. Jaeger]. TYPE: ‘‘Australia, Gippsland, Moe River, Luehmann’’ (lectotype, selected by Lewinsky (1990), H, not seen). Synonymized by Malta (1926: 75). Zygodon nanus Müll. Hal., Hedwigia 37: 135. 1898. TYPE: ‘‘New Zealand, near Greymouth, R. Helms’’ (lectotype, selected by Lewinsky (1990), H, not seen). Synonymized by Malta (1926: 75). Zygodon curvicaulis Dusén, Rep. Princeton Univ. Exped. Patagonia, Bot. 8(3): 84, fig. 13, pl. IX, figs. 6–7. 1903. TYPE: ‘‘Patagonia australis’’ (lectotype, here designated, S-B6277!; isolectotype, NY!). Synonymized by Malta (1926: 75). NOTE: Mixed with Z. magellanicus. Zygodon pangerangensis M. Fleisch., Musci Fl. Buitenzorg 2: 395, fig. 74. 1904. TYPE: ‘‘M. Fleischer, Musc. Archip. Ind., N8 280’’ (holotype, FH, not seen). Synonymized by Malta (1926: 75). Zygodon coraniensis Herzog, Biblioth. Bot. 87: 63, fig. 21g–i. 1916. TYPE: BOLIVIA. ‘‘In oberen Coranital an Baumrinde, ca. 2600 m, N8 3413’’ (holotype, JE, not seen). Synonymized by Malta (1926: 75). 491 Zygodon stresemannii Herzog, Hedwigia 57: 233. 1916. TYPE: ‘‘ Mittel-Ceram: Epiphyt der Baumfarnregion am Gunung Pinaia, ca. 2530–2750 m, col. Stresemann N8 311 u. 328’’ (syntypes, JE, not seen). Synonymized by Malta (1926: 75). Zygodon transvaaliensis Rehmann ex Sim, Trans. Roy. Soc. S. Afr. 15: 271. 1926. TYPE: SOUTH AFRICA. ‘‘On trees, Lechlaba, Houtbosch, Transvaal, Rehm. 500’’ (isotypes, PRE, TR-VENTURI!). Synonymized by Malta (1926: 75). Zygodon pseudoventricosus Müll. Hal. in Malta, Latvijas Univ. Bot. Dārza Darbi 1: 77. 1926, nom. nud. in syn. Illustrations. Figs. 17, 18A–B. Description. Plants slender to slightly robust, 0.5–3(5) cm tall, in lax to dense turfs, green to yellowish-green above, reddish-brown below. Stems erect, frequently branched. Rhizoids reddish-brown, roughened, abundant at stem base. Leaves erectflexuose when dry, spreading and flexuose when moist, (0.63–)0.85–1.45(1.80) 3 0.20–0.32 mm, lanceolate, narrower towards the base, base not or slightly decurrent, apex acute; margins plane, entire and smooth at base, papillose above; upper leaf cells rounded-hexagonal, isodiametric, strongly thickwalled, 4–10 lm in diameter, papillose; papillae 3–7 per cell, simple, blunt to subacute; basal cells subquadrate to short-rectangular, thick-walled, 9–40 3 5–15 lm, smooth, occasionally some cells with 1–2 papillae; costa ending below the apex, ca 30 lm wide in the lower 1/3, in a furrow, dorsally smooth, in section with 2 ventral guide cells and dorsal stereids. Propagula rare, fusiform to fusiform-clavate, hyaline, 67–80 3 17–19 lm, 3-celled, with only transverse septa. Dioicous. Perichaetial leaves undifferentiated. Seta 3–10 mm long, dextrorse in the distal part, sinistrorse at base; capsule erect, shortly cylindrical, pyriform or urceolate, 0.9–1.5 mm long, with 8 longitudinal ribs; exothecial bands differentiated, of 4 cell rows each; operculum conical at base, subulate, beak curved; peristome double; exostome rudimentary, of few cells, dorsal surface (OPL) almost smooth, ventral surface (PPL) completely smooth; endostome of 8 hyaline segments, dorsal (PPL) and ventral (IPL) surfaces smooth, basal membrane low, continuous and smooth. Spores papillose, (10–)13–18 lm in diameter, trilete mark weak. 492 the bryologist 109(4): 2006 Figure 17. Zygodon intermedius. A. Habit when dry. B. Habit when moist. C. Leaves. D. Apices. E. Cells in middle portion of leaf. F. Leaf basal cells. G. Leaf cross-section. H. Propagula. I. Capsule when dry. J. Peristome and spores. A, cIV, dI, F from Menzies 66 (BM 555688b); cI, dII from TIMB (BM 555688f); cII from Menzies s.n. (BM 555682c); cIII, E from Dusén 413 (S); B, J from C. & I. Skottsberg M-33 (S); G from Skottsberg 438 (S); H from Streimann HS3047 (H); I from Lara & San Miguel s.n. (HERB. LARA, Universidad Autónoma de Madrid). Ecology. Usually growing as an epiphyte on small branches of shrubs and trees, often on the underside of the twigs, occasionally at the base of the trunk of young trees; also rather frequent on rock. In the study area it has been found on Berberis, mainly on Berberis ilicifolia Forst. However, in New Zealand and Australia it is one of the species of Zygodon growing on a more diverse set of phorophytes, in wet sites as well as in more open and dry areas. Distribution (Fig. 24C). Zygodon intermedius is a widespread species. In the Patagonian and Fuegian regions, where it is known from Argentina in Rı́o Negro, Santa Cruz and Tierra del Fuego provinces and from Chile in regions V (Juan Fernández), VII, IX, X, XI and XII. Differentiation. Zygodon intermedius has been very often confused with Z. hookeri, likely because of their similar habits, the uncertainty of their respective sexual conditions (resolved by Lewinsky 1990: 136), and because the peristome of Z. intermedius has been considered very variable—simple, double or absent (Malta 1926: 76). According to Scott and Stone (1976: 246), Zygodon intermedius can be distinguished from Z. hookeri because the latter has wavy leaves with a denticulate apex, but these characters are variable in Z. hookeri (cf. discussion under that species), and not useful to separate them. However, other features distinguish the two taxa with confidence: Z. intermedius is dioicous, has perichaetial leaves not or very Calabrese: Zygodon in southern South America 493 Figure 18. SEM photographs of peristomes. A, B. Zygodon intermedius: A. Peristome and capsule mouth. B. Details of a segment and basal inner surface of the teeth. C–H. Z. jaffuelii. C. Peristome. D–G. Exostome. D. OPL, middle portion of teeth. E. OPL, apical. F. PPL, apical and in middle portion of teeth. G. PPL, basal. H. Endostome, outer surface of segment (PPL). A, B from Lara & San Miguel (HERB. LARA, Universidad Autónoma de Madrid); C–H. from Costes s.n. (FH). 494 the bryologist 109(4): 2006 slightly differentiated, a rudimentary exostome, smaller capsules and spores less than 20 lm in diameter; whereas Z. hookeri is synoicous (rarely autoicous), has perichaetial leaves well differentiated, no exostome, larger capsules and spores typically 20– 26 lm in diameter. Variability. Three varieties of Zygodon intermedius have been described, one from Java and two from Africa, none of which has been reported or found in the Andean-Patagonian and Fuegian regions. The African var. strictifolius Thér. was described as having leaves shorter and wider, very slightly (imperceptibly) acuminate, appressed and not crisped when dry (Thériot 1930: 38), and has been later reported from Rwanda and Zaire (Born et al. 1993) and Uganda (Potier de la Varde 1955). Malta distinguished his new var. dusenii, from Cameroon, by its leaves relatively short and wide, erect to patent when moist, and laminal cells larger, to 13 lm in diameter [not including the walls] (Malta 1926: 77). Finally, Fleischer (1904: 395) described the Javanese var. viridi-gracilior as having leaves shorter and wider than the type, leaf cells with thinner walls and shorter setae. The degree of variation of the characters used to separate these three varieties falls into the range for typical Z. intermedius, and no taxonomic conclusion can be reached until more material and, more importantly, the types, are studied. No specimen differs significantly from the type. Nevertheless, a specimen from the Australian Capital Territory (Streimann 11-VII-1979, BA 32442!) has abundant propagula, upper leaf cells with thinner walls than is usual for the species (consequently, the lumina are wider), with 6–7 papillae each and basal cells often with 1–2 papillae. Despite these minor differences, all other characters point to Z. intermedius. The taxon is somewhat variable in plant size, with larger plants having larger leaves (to 1.8 mm long, although they can be only 0.6 mm long, cf. Fig. 17C), and capsule shape can vary from short cylindrical to pyriform or urceolate. I think that the observed variability is driven by environmental conditions, as this taxon grows in wet as well as in rather dry sites. Selected specimens examined (209). ARGENTINA. RÍO NEGRO: Laguna Larga, Isla Victoria, 31-III-1946, De Barba s.n. (FH-BARTRAM); SANTA CRUZ: Lago San Martı́n, penı́nsula Cancha Rayada, Skottsberg 438 (S); TIERRA DEL FUEGO: Rı́o Chico, Hatcher s.n. (S-B6277). CHILE. Islas Juan Fernández, Masatierra, Bahı́a Cumberland, El Paugal, Skottsberg M53 (S); REGIÓN VII. LINARES: East of Linares along the Rı́o Atchibuena, along the road through Pejerrey 39.7 km upstream from the intersection with the road to Medina and Melado, Taylor & Gereau 11042 (MO 4423010); REGIÓN IX. MALLECO: Reserva Forestal de Malleco, ca. 70 km east of Collipulli which in turn is 34 km southeast of Angol, Landrum 409 (MO 2556517); REGIÓN X. VALDIVIA: Valdivia, Herzog 5238/a (JE-HERZOG); REGIÓN XI. AISÉN: Rı́o Exploradores, Estancia Rı́o Circo, mapa n8 4673 Monte San Valentı́n, 28-II/1-III-1967, Seki s.n. (HIRO 863-b); REGIÓN XII. TIERRA DEL FUEGO: Rı́o Cóndor site, Crosby & Castor 17462 (MO 4442293). AUSTRALIA. AUSTRALIAN CAPITAL TERRITORY: Nursery Creek, 42 km SSW of Canberra, Streimann 31393 (CHR 352127); NEW SOUTH WALES: Kosciusko National Park, Yarrangobilly Caves, Lewinsky 1884 (CHR 350097); TASMANIA: Bothwell Municipality, south end of Great Lake at intersection of road to Bronte Park, Norris 33028 (H); VICTORIA: Somer’s Park, 30 km N of Warburton, Great Dividing Range, Lewinsky 74– 307 (CHR 240266); WESTERN AUSTRALIA: The Cascade Nature Reserve, 4 km S of Pemberton, Streimann 54247, Musci Australasiae Exsicc. 476 (MA 15263). BOLIVIA. COCHABAMBA. PROV. CAPARRE: Pampa Tambo, Hermann 25273 (MO 3670891); LA PAZ. PROV. INQUISIVI: Pavionani, headwaters of the Rı́o Chimu along the Milla Milla-Aguilani Trail ca. 2 km SE of Estancia, Jankho Khalani and ca. 8 km N of Choquetanga, Lewis 89–946 d-3 (MO 3961451). NEW ZEALAND. AUCKLAND ISLAND: N side of Musgrave Inlet on route to Mt. Easton, Vitt 9054 (CHR 448821); NORTH ISLAND: Wellington Land District, Mt. Marina, 3-IX-1933, Zotov s.n. (CHR 6912); SOUTH ISLAND: Marlborough, Kowhai Bush, Kaikaura, Lewinsky 1122 (CHR 348590). INDONESIA. SUMATRA. WEST-SUMATRA: Urwälder am Südosthang des Singalang, 25-VII-1894, Schiffner s.n. (MA 941). SOUTH AFRICA. TRAANSVAL: in mont. Sechlaba, Rehmann 500 (TR-VENTURI). 10. Zygodon jaffuelii Thér., Revista Chilena Hist. Nat. 25: 300, tab. 27, fig. 1a–i. 1921. TYPE: CHILE. ‘‘Los Perales de Marga-Marga, sur troncs de Bellota, c. fr. (Costes, ann. 1915 et 1916); monts de Las Piedras (Jaffuel, ann. 1917)’’. (lectotype, REGIÓN V. VALPARAÍSO: Calabrese: Zygodon in southern South America here designated, ‘‘Costes 3-I-1916’’, PC-THÉRIOT!; isolectotypes, FH!, FH-BARTRAM!). Illustrations. Figs. 3B, 18C–H, 19. Description. Plants slender to slightly robust, (0.2–)0.8–1.7 cm tall, in relatively lax turfs, light green above, brown below. Stems erect, branched. Rhizoids reddish-brown, smooth to slightly roughened, profuse towards stems base. Leaves erect and quite twisted when dry, erect-patent when moist, (0.6–)0.8–1.5 3 0.2–0.5 mm, lanceolate, base not or slightly decurrent, apex acute; margins plane, entire and smooth at base, papillose above, entire or slightly denticulate towards apex; upper leaf cells rounded-hexagonal, thickwalled, (7–)9–11(13) lm in diameter, papillose; papillae 4–5 per cell, rarely 6, simple, low, subacute or blunt; basal cells subquadrate to short-rectangular towards the margins, (7–)13–25(36) 3 (7–)11–20 lm, larger towards the costa, 16–57 3 13–25 lm, smooth, with strongly thickened angles; costa ending below the apex, greenish, reddish in older leaves, 24– 38 lm wide in the lower 1/3, in a deep furrow, superficial cells elongate, dorsally smooth or with a few disperse papillae, especially towards apex, ventrally covered by papillose laminal cells towards the apex, in section with 2 ventral guide cells and dorsal stereids. Propagula abundant, fusiform-clavate, with thickened, brown walls when mature, 42–58 3 19–25 lm, (2–)3-celled, only with transverse septa. Dioicous. Perichaetial leaves undifferentiated. Seta 1.5–5 mm long, dextrorse in the distal part, sinistrorse at base; capsule erect, cylindrical to ellipsoidal, 1.3–1.9 mm long, with 8 longitudinal ribs; exothecial bands differentiated, of 3–4 cell rows each; operculum conical at base, rostrate to subulate, beak curved; peristome double; exostome of 8 pairs of teeth, distally truncate, patent when dry, dorsal surface (OPL) reticulate, reticulum usually smooth, rarely with few papillae, ventral surface (PPL) almost smooth or slightly roughened towards base, papillose in the upper half; endostome of 8 short, hyaline segments, dorsally (PPL) smooth, ventrally (IPL) smooth to slightly roughened. Spores papillose, (10–) 12–16 lm in diameter. Ecology. A typically epiphytic species mainly growing on trunks of ‘‘bellota,’’ Nothofagus obliqua, but it has also been collected on Populus sp. Distribution (Fig. 24B). Zygodon jaffuelii seems 495 to be endemic to central and southern Chile, where it is known from regions V, IX and X. Differentiation. Zygodon jaffuelii resembles Z. hookeri in habit. However, it is readily separated from all other Zygodon species in the study area on sporophytic grounds: its peristome is double, and the truncate exostome teeth are a unique feature in the genus. Furthermore, the basal leaf cells are collenchymatous and oblate to short-rectangular, and the walls of the mature propagula are brown. Zygodon jaffuelii has been occasionally confused with Zygodon hookeri var. leptobolax. However, Z. jaffuelii is a dioicous species with a double peristome, undifferentiated perichaetial leaves, brown propagule walls and smaller spores (always less than 16 lm in diameter). On the other hand, Z. hookeri var. leptobolax is a synoicous species lacking an exostome, with differentiated perichaetial leaves, usually hyaline, greenish or yellowish propagula and larger spores (always more than 18 lm in diameter). Variability. Zygodon jaffuelii hardly varies. The only character showing some variability is seta length, ranging from 1.5 to 5 mm. Plants are usually 0.8–1.7 cm tall, but some occasional specimens only reach 0.2 cm. No other structure shows significant variation. Zygodon jaffuelii has been considered a synonym of Z. liebmannii Schimp. ex Müll. Hal. (Allen 2002; Grout 1946). However, Z. liebmannii, a rare species with few specimens known, most of which have been studied for this treatment, has lax, longer (35–45 lm), thin-walled and non-collenchymatous basal leaf cells, an almost percurrent costa and a commonly decurrent base. On the contrary, Z. jaffuelii has firm, shorter (13–25(36) lm), and collenchymatous basal cells, a costa that always ends a short distance from the apex and the leaf base is not or only slightly decurrent. Furthermore, Z. jaffuelii commonly has abundant propagula, while all the studied specimens of Z. liebmannii, including all known types, lack propagula. Contrary to my observations, Malta (1926) described propagula for Z. liebmannii, morphologically similar to those in Z. jaffuelii. I have studied two out of the three specimens of Z. liebmannii cited by Malta (1926)—Pico de Orizaba, Liebmann s.n. and Cima, Pringle 10546—and I could not find the propagula he reported. Vitt (1994) described Z. liebmannii as having propagula with 7–8 cells and 496 the bryologist 109(4): 2006 Figure 19. Zygodon jaffuelii. A. Habit when dry. B. Habit when moist. C. Leaves. D. Apices. E. Cells in middle portion of leaf. F. Leaf basal cells. G. Leaf cross-sections. H. Propagula. I. Peristome (inner view) and spores. A from Jaffuel s.n. (FH); B–I from Costes s.n. (PC). Calabrese: Zygodon in southern South America longitudinal as well as transverse septa. In PC there are two type specimens of Z. jaffuelii (with duplicates in FH-BARTRAM, FH-FLEISCHER, MO and NY, all seen) annotated by D. Vitt as Z. liebmannii. One of them is in fact Z. jaffuelii, but the other is typical Z. papillatus. The propagula of Z. papillatus have 7–8 cells and longitudinal as well as transverse walls, and this specimen of Z. papillatus seems to be the base of the confusion in Vitt (1994). Selected specimens examined (23). CHILE. REGIÓN V. VALPARAÍSO: Los Perales (Marga Marga) sur troncs de Bellota, 3-I-1916, Jaffuel s.n. (FH, MO 3987831); REGIÓN IX. CAUTÍN: Dept. Villarica, Pucon, Hosseus 156 (JE-HERZOG); REGIÓN X. VALDIVIA: Entrance lane to UACH campus, Isla Teja, Valdivia, Prins RP-6-22851b (MO 3665841). Specimens examined of Zygodon liebmannii. MEXICO. VERACRUZ: Orizaba, Liebmann s.n. (BM-SCHIMP. 555687 b, BM-SCHIMP. 555687, both types). Zygodon reinwardtii-hookeri complex The Zygodon reinwardtii-Zygodon hookeri complex lacks formal nomenclatural circumscription, although I have included in it several species of Zygodon difficult to distinguish that share a unique combination of characters. They are usually synoicous, have differentiated perichaetial leaves, a simple peristome of eight endostomial segments, papillose and large (frequently greater than 18 lm in diameter) spores and long-rostrate to subulate opercula. This complex is represented in the study area by Zygodon reinwardtii, Z. hookeri var. hookeri and Z. hookeri var. leptobolax. Although the typical expressions of these three taxa have distinctive features, the morphological characters show wide variation, which makes it almost impossible to name specimens with intermediate characteristics. Specimens from the entire distribution range of the three taxa have been examined, but no clear differential morphological characters were found, consequently more studies are needed to clarify the validity of the taxa in this complex. 11. Zygodon reinwardtii (Hornsch.) A. Braun ex Bruch & Schimp., Bryol. Europ. 3: 41 (fasc. 4, monogr. 9). 1838; Syrrhopodon reinwardtii Hornsch., Nova Acta Phys.-Med. Acad. Caes. Leop.-Carol. Nat. Cur. 14(2): 700, tab. 39, fig. a. 1829. TYPE: ‘‘Hab. in Iava [Blume, Reinwardt]’’ 497 (type, BM?; there are no original materials at L, Touw, pers. comm.). Zygodon moritzianus Müll. Hal., Linnaea 19: 199. 1846. TYPE: ‘‘Columbia, prov. Mérida, in montibus nivosis, Moritz’’. Synonymized by Malta (1926: 118). Zygodon denticulatus Taylor, London J. Bot. 6: 329. 1847. TYPE: ECUADOR. ‘‘Andes Quitenses; Monte Pichincha, Will. Jameson, Nov. 1846’’ (lectotype, here designated, G-027226!; isolectotype, G027222!). Synonymized by Malta (1926: 118). Zygodon cylindricarpus Müll. Hal., Bot Zeitung (Berlin) 11: 59. 1853. TYPE: INDIA. ‘‘Nilghiri’’. Synonymized by Malta (1926: 118). Zygodon subdenticulatus Hampe, Ann. Sci. Nat. Bot., V, 4: 326. 1865. TYPE: COLOMBIA. ‘‘Bogota, Pacho, Chiquinquira, Guadalupe, Tequendama, Canoas et Paramo Choachi, altit. 2090–3600 m, in sylv. sub n8 2092, 2126, 2129 et 2145, leg. A. Lindig’’ (syntypes, G-027232!, G-027231!). Synonymized by Malta (1926: 118). Zygodon andinus Mitt., J. Linn. Soc. Bot. 12: 236. 1869. TYPE: ECUADOR. ‘‘Andes Quitenses, in monte Pichincha (9000 ped.) in devexu australi, Spruce 117’’ (holotype NY, not seen; isotype, G-027235!). Synonymized by Malta (1926: 118). Zygodon circinatus Schimp. ex Besch., Mém. Soc. Sci. Nat. Cherbourg 16: 187. 1872. TYPE: MEXICO. ‘‘Cordova (F. Müller)’’ (isotype, BM?, not found). Synonymized by Malta (1926: 118). Zygodon breviciliatus Thwaites & Mitt., J. Linn. Soc. Bot. 13: 304. 1873. TYPE: ‘‘In Ceylon, Dr. Thwaites’’ (holotype, Thwaites 73, NY, not seen). Synonymized by Malta (1926: 118). Zygodon glaziovii Hampe, Vidensk. Meddel. Dansk Naturhist. Foren. Kjøbenhavn, III, 6: 142. 1874. TYPE: BRAZIL. ‘‘Serra do Itatiaia, Dusén, 1902’’ (isotype, HBG!). Synonymized by Malta (1926: 118). Zygodon ceratodontoides Müll. Hal., Flora 58: 535. 1875. TYPE: ‘‘Colombia, Ocanna, leg. Wallis.’’ Synonymized by Malta (1926: 118). Zygodon caldensis Ångstr., Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 33(4): 15. 1876. TYPE: BRAZIL. ‘‘Caldas, Henschen.’’ Synonymized by Malta (1926: 118). Zygodon fendleri Müll. Hal., Linnaea 42: 484. 1879. TYPE: ‘‘Tovar, 1854–55, Fendler Musci Venezue- 498 the bryologist 109(4): 2006 lenses N8 28’’ (lectotype, here designated, G027227!). Synonymized by Malta (1926: 118). Zygodon gymnus Müll. Hal., Linnaea 42: 484. 1879. TYPE: ‘‘Tovar, 1854–55, Fendler Musci Venezuelenses N8 27’’ (lectotype, here designated, G027224!; isolectotype, HBG!). Synonymized by Malta (1926: 119). Zygodon borbonicus Besch., Ann. Sci. Nat. Bot., VI, 9: 353. 1880. TYPE: ‘‘La Réunion: G. de l’Isle, 1875, n8 420; P. Lépervanche, 1877.’’ Synonymized by Malta (1926: 119). Zygodon hyadesii Besch., Bull. Soc. Bot. France 32: LX. 1885; Zygodon reinwardtii var. hyadesii (Besch.) Malta, Latvijas Univ. Bot. Dārza Darbi 1: 121. 1926. TYPE: ‘‘Terre de Feu (Dr. Hyades); Patagonia occidentale, ı̂le Wellington: Port-Eden (Dr. Savatier)’’. (lectotype, here designated, CHILE. ‘‘Terre de Feu. Hyades,’’ NY!), syn. nov. Zygodon madacassus Schimp. in Wright, J. Botany 26: 264. 1888, nom. nud. Zygodon paucidens Müll. Hal., Nuovo Giorn. Bot. Ital. 4: 120. 1897. TYPE: BOLIVIA. ‘‘Germain [. . .] 1889 prope Choquecamata provinciae Cochabamba Bolivianae alto-montosae ex altitudine pedum 10–12,000, ut opinor, collectas’’ (lectotype, here designated, G-027225!). Synonymized by Malta (1926: 119). Zygodon volkensii Broth., Bot. Jahrb. Syst. 24: 241. 1897. TYPE: TANZANIA. ‘‘Kilimanscharo’’. Synonymized by Malta (1926: 119). Zygodon dives Müll. Hal., Bull. Herb. Boissier 6: 94. 1898. TYPE: BRAZIL. ‘‘Serra do Itatiaia, Dusén, 1902’’ (lectotype, here designated, HBG!). Synonymized by Malta (1926: 119). Zygodon coarctatus Schimp. ex Paris, Index Bryol. 1372. 1898, nom. nud. Zygodon argutidens Broth. in Mildbr., Wiss. Erg. Deut. Zentr.-Afr. Exped., Bot. 2: 148, tab. 13, fig. 8. 1910. TYPE: UGANDA/ZAIRE. ‘‘Ruwenzori: Butagu-Tal, Ericaceen-Stämme und Zweige, halbkugelige Polster bilden, ca. 3300 m ü. M. (reichlich fruchtend im Febr.—1908—n. 2616’’ (holotype H?, not found). Synonymized by Malta (1926: 119). Zygodon reinwardtii var. madacassus Cardot in A. Grandid. & G. Grandid., Hist. Phys. Nat. Polit. Madagascar 39: 229. 1915, nom. inval., not accepted by author (ICBN St. Louis, art. 34.1). Zygodon reinwardtii var. subintegrifolius Malta, Latvijas Univ. Bot. Dārza Darbi 1: 122, fig. 69d. 1926. TYPE: ‘‘Brasilien, Caldas, Henschen; Columbien, Bogota, Lindig.’’ Synonymized by Anderson et al. (1990: 498). Zygodon lindigii Hampe ex Malta, Latvijas Univ. Bot. Dārza Darbi 1: 178. 1926, nom. nud. Pleurozygodontopsis decurrens Dixon, Ann. Bryol. 12: 51. 1939. TYPE: ‘‘Sumatra, Gunong Losir, Atjeh, Gajolanden, 2940 m, 5-II-1937, van Steenis 10159’’ (lectotype, here designated, BM-DIXON 4044!). Synonymized by Eddy (1996: 16). Illustrations. Figs. 2A, 3A, 20. Description. Plants slender to somewhat robust, 1.0–2.8 cm tall, in lax turfs, light-green to yellowishgreen above, brown below. Stems erect, branched. Rhizoids reddish-brown, smooth, roughened or slightly papillose. Leaves erect and 6 twisted when dry, spreading and flexuose when moist, (0.9–)1.1–2.3 3 (0.19–)0.27–0.49 mm, lanceolate, keeled, base decurrent, apex acute; margins usually undulate, less frequently almost plane, entire at base, papillose above, usually dentate at apex and in the upper 1/3, rarely entire or with 1–2 teeth at apex; upper leaf cells rounded-hexagonal, isodiametric, thick-walled, 8–12 lm in diameter, papillose; papillae (2–)4–6 per cell, simple, acute to subacute, rarely blunt; basal cells subquadrate to rectangular, thick-walled, 18–2336–10 lm, shorter towards margins, 9–15 3 6–8 lm, smooth, ocasionally with 1–2 papillae; costa ending below the apex, 28–45 lm wide in lower 1/3, in a furrow, dorsally smooth or with a few dispersed papillae towards the apex, in section with 2 guide cells and dorsal stereids. Propagula infrequent and scarce, fusiform, fusiformclavate or clavate, with hyaline or greenish-hyaline, rarely brown walls, 45–167 3 17–27(36) lm, usually 3–7-celled with only transverse septa, rarely with more cells and with transverse and longitudinal septa. Synoicous. Perichaetial leaves differentiated, erect when moist, 1.5–1.7 3 0.3–0.4 mm, lanceolate, apex acute-acuminate; margins entire. Seta (5–)9–15 mm long, dextrorse in the distal part, sinistrorse at base; capsule erect, rarely oblique, cylindrical or fusiform, sometimes slightly gibose, narrowed towards capsule mouth, 1.5–3.2 mm long, with 8 ribs throughout; exothecial bands slightly differentiated, of 4–6 cell rows each, interrupted by a continuous ring of 2–6 smaller Calabrese: Zygodon in southern South America 499 Figure 20. Zygodon reinwardtii. A. Habit when dry. B. Habit when moist. C. Leaves. D. Perichaetial leaf. E. Apices. F. Leaf basal cells. G. Leaf cross-section. H. Propagula. I. Wet capsule. J. Capsules when dry. K. Peristome and spores. A, B, cII, eII, I, J from P. de la Bathie (PC-THÉRIOT); cI, hII from Ule 131 (G); cIV, D, hI from Fendler 27 (G); cIII, eI from Skottsberg 435 (S); cV, K from Matteri & Schiavone TBPA-B 2276 (BA); F, G from Sparre 2044 (S); hIII from Dusén s.n. 29-II-1896 (S); hIV from Germain s.n. (G). 500 the bryologist 109(4): 2006 cells around capsule mouth; operculum conical at base, subulate, beak curved; peristome simple, exostome absent; endostome of 8 hyaline segments, dorsal (PPL) and ventral (IPL) surfaces smooth, sometimes slightly roughened, basal membrane low, continuous and smooth. Spores papillose, (15–)18–25 lm in diameter, trilete marks absent. Ecology. Zygodon reinwardtii is typically an epiphyte in Quercus spp., Bonnetia roraimae Oliv. or Nothofagus spp. forests, usually on small branches and twigs of shrubs and trees like Drimys winteri J.R. Forst. & G. Forst., Polylepis sp., Erythrina sp., Hypericum sp., diverse Ericaceae or ferns like Blechnum. It is also occasionally found on soil and rocky areas with Racomitrium crispulum (Hook.f. & Wilson) Hook.f. & Wilson. In the Americas it is very common in the Venezuelan and Colombian paramos. Distribution (Fig. 24B). This species has a wide distribution, especially in the tropics. It is known from Mexico, Central America, South America (from Venezuela to Tierra del Fuego), Africa, Madagascar, India, Sri Lanka and SW Asia (China). It has been also reported from Alaska, Philippines, Java and New Guinea, but these records are likely confusions with Z. hookeri var. hookeri, as explained above (p. XX). Malta (1926) and Lewinsky (1990) discussed the variability of Zygodon reinwardtii and Z. hookeri, and concluded that the plants from Australia, Tasmania and New Zealand belong to Z. hookeri. In the study area it is known from Santa Cruz and Tierra del Fuego Provinces of Argentina, and from regions X, XI and XI of Chile. Differentiation. Zygodon reinwardtii is closely related to the also variable Z. hookeri, and both can be difficult to distinguish. Only typical expressions of both are clearly separated: Zygodon reinwardtii has decurrent leaves strongly dentate at apex, while Z. hookeri var. hookeri has slightly decurrent leaves denticulate at apex. Propagula in the latter are clavatefusiform, smaller (3-celled), and never with longitudinal walls. In addition, Z. hookeri has basal leaf cells usually larger and capsules are always cylindrical. Variability. Typical Zygodon reinwardtii has strongly undulate leaves sharply dentate at the apex, sometimes in the upper 1/3. Nevertheless, both features vary considerably. Some leaves have only one or two well-developed teeth, hardly visible, or totally lack them, and specimens intermediate in marginal teeth development are common. Similarly, leaf undulation is very variable, even in the same specimen. Regarding propagula, although they are a stable structure with a set of taxonomically important characters for most Zygodon species, in Z. reinwardtii they are so variable that they seem to represent different taxa. Most Z. reinwardtii specimens have hyaline or greenish-hyaline fusiform to clavate-fusiform propagula, with only transverse septa. Only a specimen from Choquecamata (Bolivia) has brown to greenish-brown, clavate propagula with transverse and longitudinal septa. Despite these differences, propagula are not frequent or abundant in Z. reinwardtii, which could hamper correct estimation of this variability. Sporophytically Z. reinwardtii is a more stenotypic taxon, with 6 cylindrical to fusiform and slightly gibbous capsules 1.5–3 mm long. An anomalous expression, f. cerantodontoiodea Malta (1926: 121), described from Colombia on the basis of its strongly curved capsules, was unavailable for study. On the basis of gametophyte differences as well as geographical providence, many taxa have been described around Z. reinwardtii. Many of them were subsequently synonymized with typical Z. reinwardtii, mainly by Malta (1926), with only var. hyadesii (Tierra del Fuego and West Patagonia), var. ruwenzorensis (Thér. & Naveau) Demaret (Ruwenzori) and var. capillicaulis (Müll. Hal.) Malta (Brazil), being currently recognized. The type and the many specimens previously identified as Z. reinwardtii var. hyadesii, that have been examined for this study, have leaves that fall into the range of variation observed for the typical expression. There is no correlation between the paucity of apical teeth, on which basis this variety was described, and any other feature; in fact most specimens belong to Z. hookeri var. leptobolax. Regarding var. ruwenzorensis and var. capillicaulis, I have reached the same conclusion after studying specimens from Ruwenzori (Uganda/Zaire) and Serra do Itatiaia (Brazil), although I delay formal synonymization until types of both are studied. Finally, Cardot (in Renauld & Cardot 1915: 229) also mentioned that specimens from Madagascar labelled Z. madacassus have less dentate leaves, smaller laminal cells and longer seta. However, he did not accept those differences enough to consider it different from typical Z. reinwardtii, even at varietal rank (ICBN St. Louis, Art. 34.1, Ex. 3), an opinion with which I concur. Calabrese: Zygodon in southern South America Selected specimens examined (127). ARGENTINA. Lago San Martı́n, Brazo NW, Skottsberg 436 (S); TIERRA DEL FUEGO: Lago Fagnano, Skottsberg 776 (S). CHILE. REGIÓN X. LLANQUIHUE: Puerto Varas, Ensenada, Sparre 2044 (S, FH-BARTRAM); REGIÓN XI. AISÉN: Rio Aysén, 30-I-1897, Dusén s.n. (S); REGIÓN XII. ÚLTIMA ESPERANZA: Bahı́a Bellavista, Matteri & Schiavone TBPA-B 2276 (BA). BOLIVIA. COCHABAMBA. PROV. CHAPARE: sureste de Laguna Curani, Churchill et al. 19840 (MO 5211664); LA PAZ. PROV. INQUISIVI: Valle de Chimu, 2 km NW of Estancia Chimu and 6 km NE of Choquetanga, Lewis 38804 d-1 (MO 3960868). BRAZIL. RIO DE JANEIRO: Parque National de Itatiaia, Pico das Agulhas Negras, N of Engo Passos and 12.4 km NE of União, Vitt 21574 (MO 2555716). COLOMBIA. ANTIOQUIA: Municipio La Ceja, 5,5 km SE de La Ceja hacia La Unión, Churchill & Sastre-De Jesús 12855 (H); BOYACÁ: Municipio de Duitama, around Paramo ‘‘La Rusia’’, Ireland 23568 (CANM 308703, MO 3663203); CAUCA: Valle del Cauca, Darien, ‘‘Páramo del Duende’’, Cerro Calima, ca. 60 km N de Cali, Churchill 19556 (MO 5125845); CUNDINAMARCA: Tausa, Cuchilla Laguna Seca, alrededores Laguna Verde, Churchill et al. 19369 (MO 5125608); HUILA: páramo de Las Papas, cerros y alrededores de las lagunas La Magdalena y Santiago, Bischler 872 (MO 5137008); NARIÑO: municipio de Pasto, Correg. de La Laguna, alrededores Alto Zapallurco, Ramı´rez & Salas 10835 (MO 4430748). DEMOCRATIC REPUBLIC OF THE CONGO. Massif du Ruwenzori, [? illeg.], VII-1929, Humbert s.n. (PC-P. DE LA VARDE). ECUADOR. Cordillera, Jaeger s.n. (TRVENTURI); NAPO: along road Baeza-Quito, near Cuyuga, van der Werff et al. 13455A (MO 4420448); PICHINCHA: vicinity of Rı́o Amalbi, along road leading W from Nono toward Tandayapa, N slopes of Mt. Pichincha, Crosby 10540 (MO 2330102); QUITO: Guayrapata, Spruce 116 (FH-BARTRAM). MADAGASCAR. Mt. Tsaratanana, IV-1924, P. de la Bathie (PC-THÉRIOT). PERU. CAJAMARCA: Puente Bajo (Chalchuayacu) zw. Encañada u. Celendin, Hegewald & Hegewald 6615 (MO 3670867); CHAPAPOYAS: Dpto. Amazonas, Chanchillo zw. Balsas u. Leimebamba, Hegewald & Hegewald 6780 (MO 3670893); OXAPAMPA: Dpto. Pasco, ca. 5 km von Oxapampa in Richtung Pozuzo, Hegewald & Hegewald 8441 (MO 3670866); URUBAMBA: Dpto. Cuzco, Machu Picchu, Hegewald & Hegewald s.n. (MO SANTA CRUZ: 501 5147610); YUNGAY: Dpto. Ancash, An der Laguna Llanganuco, Hegewald & Hegewald 7529 (MO 3670869). VENEZUELA. BOLÍVAR: Distrito Piar, Macizo del Chimantá, sector centro-noreste del Chimantátepui, cabeceras orientales del Caño Chimantá, Steyermark et al. 128052-A (MO 3061984); MÉRIDA: Sierra Nevada, teleférico Loma Redonda, camino hacia los nevados, Cleef & Huber 4787 (MO 3673453). 12. Zygodon hookeri Hampe, Linnaea 30: 632. 1869. TYPE: AUSTRALIA. ‘‘Hab. ad arbores, mont. Grampian.’’ [1854, Dr. F. Mueller 5] (holotype BM!). Description. Plants slender to slightly robust, (0.3–)1.2–3.5 cm tall, in loose turfs, green to yellowish-green above, reddish-brown below. Stems erect, branched. Rhizoids reddish-brown to yellowish, smooth or slightly roughened, ascending by stems. Leaves erect, 6 twisted and keeled when dry, spreading and flexuose when moist, (0.9–)1.35–2.38 3 (0.25–)0.35–0.55 mm, lanceolate, sometimes narrowed towards the base, base slightly decurrent, apex acute; margins undulate to plane, entire below, papillose above, denticulate to entire at apex; upper leaf cells rounded-hexagonal, 6 isodiametric, thickwalled, (6–)9–14 lm in diameter, papillose; papillae 3–9 per cell, usually simple, subacute, rarely blunt; basal cells short-rectangular to rectangular, thickwalled, (10–)18–44(63) 3 6–15 lm, smooth or with 1–2 papillae; costa ending below the apex, 30–42(51) lm wide in lower 1/3, in a deep furrow, superficial cells elongate on both sides, dorsally smooth in lower 2/3, smooth or papillose towards the apex, in section with 2 ventral guide-cells and dorsal stereids. Propagula infrequent or common, scarce to abundant, fusiform to clavate-fusiform, with hyaline or greenish-hyaline (rarely brown) walls, 36–81(90) 3 12–30 lm, (2–)3–5(6)-celled, with only transverse septa, ocassionally with transverse and longitudinal septa and then to 10-celled. Synoicous (very rarely autoicous in Australia, see Variability). Perichaetial leaves differentiated, erect when moist, 0.9–1.8 3 0.27–0.39 mm, lanceolate, apex acute-acuminate; margins entire or with some papillae towards the apex; cells elongate, smooth at base, smaller and papillose towards the apex. Seta (4–)10–15 mm long, dextrorse in the distal part, sinistrorse at base; capsule erect, cylindrical, 1.3–2.5 mm long, with 8 ribs througout; exothecial bands differentiated, of 4–5 cell 502 the bryologist 109(4): 2006 rows each, interrupted by a continuous ring of 3–6 smaller cells around capsule mouth; operculum conic at base, subulate, beak curved; peristome simple, exostome absent; endostome of 8 hyaline segments, dorsal (PPL) and ventral (IPL) surfaces smooth, occasionally slightly roughened, basal membrane low, continuous and smooth. Spores papillose, (18–)20–26 lm in diameter, trilete mark absent. 12a. Zygodon hookeri Hampe var. hookeri Zygodon mucronatus Müll. Hal., Hedwigia 37: 136. 1898, nom. illeg., non Broth. 1896; Z. submucronatus Paris, Index Bryol. Suppl. 1: 330. 1900. TYPE: ‘‘New Zealand’’ (isotype, GOET). Synonymized by Lewinsky (1990: 133). Illustrations. Figs. 2B, 21. Diagnosis. Plants slender to slightly robust, (0.4–) 1.2–3.5 cm tall. Leaves 6 twisted when dry, spreading and flexuose when moist, (0.9–)1.35–2.38 3 0.35–0.55 mm, lanceolate; margins undulate, entire at base, papillose above, typically denticulate, occasionally entire at apex; upper leaf cells (6–)9–12 lm in diameter, 3–6(9) papillae per cell; basal cells rectangular, 18–44 3 6–13 lm. Propagula infrequent, scarce, with hyaline or greenish-hyaline walls, 36–52 3 12–20 lm, 3-celled, with only transverse septa. Selected specimens examined (48). ARGENTINA. SANTA CRUZ: Dpto. Lago Argentino, Seno Mayo, pequeña bahı́a al NE del Seno, Matteri & Schiavone CM 4910 (BA, MA). CHILE. REGIÓN XII. ÚLTIMA ESPERANZA: glaciar del cerro Balmaceda, margen occidental del Puerto Toro, Matteri TBPA B 2714 (BA). AUSTRALIA. TASMANIA: Bothwell Municipality, south end of Great Lake at intersection of road to Bronte Park, Norris 33028.(H); VICTORIA: Mt. William, Grampians, 19 km SSE of Halls Gap, Streimann HS3031 (H). NEW ZEALAND. NORTH ISLAND: South Auckland, near Atiamuri, south of Ratorwa, Allison 486 (CHR 523861); SOUTH ISLAND: Nelson Lakes Nat. Park, St. Anould, Frahm 23–3 (CHR 503103). 12b. Zygodon hookeri var. leptobolax (Müll. Hal.) Calabrese, comb. nov. Zygodon leptobolax Müll. Hal., Hedwigia 38: 113. 1899. TYPE: SOUTH AFRICA. ‘‘Prom. bonae spei, in fruticetis prope Rondebosch, aug. 1875, c. fr. vetustis vel valde juvenilibus: Dr. A. Rehmann, Coll. N8 379,’’ but really: Cape, near Rondebosch, Rehmann 499 (lectotype, here designated, PRE!). NOTE: Dixon and Gepp (1923) published a checklist of Rehmann’s collections from South Africa in which Rehmann 379 belongs to Brachythecium afro-velutinum Müll. Hal. The only collection of Z. leptobolax is Rehmann 499, published in his exsiccata with the number 147. Magill (1980) and Magill and Van Rooy (1998) also considered this collection as the type of Z. leptobolax. Zygodon inermis Dusén ex Malta, Latvijas Univ. Bot. Dārza Darbi 1: 174. 1926; Zygodon hyadesii var. inermis Dusén, nom. nud. in sched. TYPE: ‘‘Chile australis, ins. Quiriquina in truncis arb., P. Dusén, 20-IX-1896’’ (lectotype, here designated, S!; isolectotype, PC!), syn. nov. Zygodon theriotii Herzog, Arch. Esc. Farm. Fac. Ci. Méd. Córdoba (Argentina) 7: 47. 1939. TYPE: ‘‘Chile: Prov. Cautin, Dep. Villarrica: Pucón (N8 803, 804 y 822); Prov. Chiloé, Dep. Llanquihué: Petrohué (N8 497, 521 y 532)’’ (lectotype, here designated, Hosseus 822, JE-HERZOG!; syntypes, Hosseus 497, Hosseus 532, Hosseus 803, Hosseus 804, all JE-HERZOG!), syn. nov. Illustration. Fig. 22. Diagnosis. Plants slender to slightly robust, (0.3–) 0.8–1.8 cm tall. Leaves twisted when dry, spreading and flexuose when moist, (1.05–)1.3–2.1 3 (0.25–) 0.31– 0.49 mm, lanceolate; margins plane, sometimes somewhat undulate, entire at base, papillose above, typically entire at apex, although occasionally with few small teeth; upper leaf cells 8–14 lm in diameter, with (4–)6– 9 papillae per cell; basal cells short-rectangular to rectangular, (10–)19–40(63) 3 6–15 lm. Propagula common, abundant, with hyaline, rarely brown or greenish-hyaline walls, 45–81(90) 316–30 lm, (2–) 3–5(6)-celled, with only transverse septa., rarely with also longitudinal septa and consequently to 10-celled. Selected specimens examined (38). CHILE. REGIÓN VIII: Chile australis, Ins. Quiriquina, Dusén 226 (H); REGIÓN IX. CAUTÍN: Dep. Villarrica, Pucón, Hosseus 804 (JE-HERZOG, S-B6271, syntype); REGIÓN X. LLANQUIHUE: Lac. Llanquihue, Dusén 701 (S); REGIÓN XI. AISÉN: Rı́o Exploradores, Estancia Rı́o Circo, 2/5-III-1967, Seki s.n. (HIRO 1133); REGIÓN XII: Otway, Puerto Pomar, Skottsberg 435 (FH-BARTRAM). Ecology. Zygodon hookeri usually grows on tree trunks, shrub branches and fallen logs in forests, more rarely on rotten wood. In the study area it has been found on Nothofagus betuloides, Nothofagus pumilio, Berberis spp. and Austrocedrus chilensis. In New Calabrese: Zygodon in southern South America 503 Figure 21. Zygodon hookeri var. hookeri. A. Habit when dry. B. Habit when moist. C. Leaves. D. Perichaetial leaf. E. Apex. F. Cells in middle portion of leaf. G. Leaf basal cells. H. Leaf cross-sections. I. Propagula. J. Capsule when dry. K. Peristome and spores. A, cII, E, iI, J from Matteri & Schiavone CM 4910 (BA); B, cI, D, F, G, iII from Müller 5 (BM); H, iIII from Linbolt 236 (CHR); kI from Brownlie 824 (CHR); kII from Simpson 118 (CHR). 504 the bryologist 109(4): 2006 Figure 22. Zygodon hookeri var. leptobolax. A. Habit when dry. B. Habit when moist. C. Leaves. D. Perichaetial leaf. E. Apices. F. Cells in middle portion of leaf. G. Leaf basal cells. H. Leaf cross-section. I. Propagula. J. Peristome and spores. A from Hosseus 497 (JE); B, cI, iIII, J from Dusén s.n. 20-IX-1896 (PC); cII from Rehmann 499 (PRE); cIII, eI, F, G, H from Hosseus 804 (S-B6271); D from Dusén s.n. IV-1897 (S); E from Hosseus 822 (JE); eII, iI from Rehmann 499 (PRE); iII from Hosseus 822 (JE); iIV from Mahu 9274 (MO); iV from Schwabe 45-a (JE). Calabrese: Zygodon in southern South America 505 Figure 23. Distribution of Zygodon in southern South America: A. Z. menziesii (solid circle) and Z. obtusifolius (open circle). B. Z. pentastichus (solid circle) and Z. magellanicus (open circle). C. Z. papillatus. D. Z. chilensis. 506 the bryologist 109(4): 2006 Figure 24. Distribution of Zygodon in southern South America: A. Z. pichinchensis (solid circle) and Z. bartramioides (open circle). B. Z. reinwardtii (solid circle) and Z. jaffuelii (open circle). C. Z. intermedius. D. Z. hookeri var. hookeri (open circle) and Z. hookeri var. leptobolax (solid circle). Calabrese: Zygodon in southern South America Zealand it is also common on Nothofagus spp., and has been rarely reported from rocks. Distribution (Fig. 24D). Zygodon hookeri has a sub-Antarctic distribution. Zygodon hookeri var. hookeri is known from Australia, New Zealand and southern South America. In the study area it is known from Santa Cruz Province of Argentina, and Región XII of Chile. Zygodon hookeri var. leptobolax is known from South Africa and southern South America; it has been found in regions VIII, IX, X, XI and XII of Chile. Differentiation. Zygodon hookeri var. hookeri is very similar to Z. reinwardtii, from which can only be clearly distinguished when both are in their typical expressions: decurrent leaves strongly dentate at apex in Z. reiwardtii, and slightly decurrent and denticulate leaves in Z. hookeri var. hookeri. Other characters such as propagula size and shape are scarcely useful because they are rarely observed in both taxa. Capsules are usually of no use in distinguishing these taxa, except in the rare occasions when they are 6 fusiform and slightly gibbose in Z. reinwardtii (always cylindrical in Z. hookeri var. hookeri). My results show that these taxa could be synonyms, with Z. reinwardtii being the oldest name. Confusion with other species of similar habit, such as Z. jaffuelii and Z. intermedius is unlikely. These two species are dioicous, have undifferentiated perichaetial leaves and double peristomes, while Z. hookeri is synoicous, has differentiated perichaetial leaves, and a single peristome. Variability. Zygodon hookeri varies mainly in leaf lamina undulation and apex denticulation, as well as propagule morphology. Leaves are commonly undulate, although plane leaves have also been observed. Leaves apices in the type variety are denticulate, but vary from denticulate to entire in var. leptobolax. Finally, propagula are usually fusiform to clavate-fusiform, hyaline and only with tranverse septa, although two collections from the northern Andean-Patagonian region (Mahu 9274 and 8629, MO!), have brown, clavate propagula with longitudinal as well as transverse septa (Fig. 22IIV); both specimens grew on Austrocedrus chilensis in a more mesic forest. Regarding sexual condition, two Australian collections of Z. hookeri var. hookeri (Streimann 2873 and 3031, H!) are autoicous, although this taxon is 507 almost always synoicous (always in the South American specimens studied). Traditionally, Zygodon leptobolax has been considered endemic to South Africa, and Z. inermis and Z. theriotii endemics from southern South America. However, all type materials of the three were studied and no differences among them were found, so I have concluded that the three names represent the same taxon. These types are sporophytically identical to the type of Z. hookeri, which only differs from them by the more undulate and denticulate leaves, and uncommon, smaller propagula. In the study area there are specimens exactly matching the type of Zygodon hookeri, others are identical to South African materials (i.e., Z. leptobolax), while others are intermediate between these two morphological extremes. Pending further taxonomic studies on African Zygodon I prefer to maintain Z. leptobolax at the varietal rank. ACKNOWLEDGMENTS I thank the curators of BA, BCRU, BM, CHR, FH, G, H, HBG, HIRO, JE, MA, MO, NY, PC, PRE, S, TR-VENTURI, UBC and UC for loan of specimens. I also thank my Ph.D. dissertation advisors, M. J. Elı́as (Universidad de Salamanca) and F. Lara (Universidad Autónoma de Madrid), for their help and support. 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A taxonomic revision of Zygodon (Orthotrichaceae) in southern South America

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