1203 A taxonomic revision of Helichrysum sect. Stoechadina (Asteraceae, Gnaphalieae) Mercè Galbany-Casals, Llorenç Sáez, and Carles Benedı́ Abstract: A taxonomic revision of Helichrysum sect. Stoechadina, a section with a Mediterranean distribution, is presented. Taxonomic, nomenclatural, morphological, chromosomal, geographical, and ecological data are provided for each taxon. Eleven taxa are recognized, two lectotypifications are proposed, and a taxonomic key and a sectional description are included. The following new combinations are proposed: Helichrysum italicum subsp. siculum (Jord. & Fourr.) Galbany, L. Sáez & Benedı́ comb. nov. and Helichrysum italicum subsp. picardii (Boiss. & Reut.) Galbany, L. Sáez & Benedı́ comb. nov. Key words: Asteraceae, Gnaphalieae, endemism, Helichrysum, Mediterranean region, infraspecific variation. Résumé : Les auteurs présentent une révision taxonomique des Helichrysum sect. Stoechadina, incluant toutes les espèces avec distribution méditerranéenne. On présente pour chaque taxon des données sur la taxonomie, la nomenclature, la morphologie, les chromosomes, la géographie et l’écologie. On reconnaı̂t 11 taxons, on propose deux lectotypifications et une clé taxonomique, ainsi qu’une description de la section. On propose les combinaisons nouvelles suivantes : Helichrysum italicum subsp. Siculum (Jord. & Fourr.) Galbany, L. Sáez & Benedı́ comb. nov. et Helichrysum italicum subsp. picardii (Boiss. & Reut.) Galbany, L. Sáez & Benedı́ comb. nov. Mots clés : Asteraceae, Gnaphalieae, endémisme, Helichrysum, région méditerranéenne, variation intraspécifique. [Traduit par la Rédaction] Introduction The genus Helichrysum Mill. (Gnaphalieae) is distributed throughout the African continent, Madagascar, the Mediterranean basin, Macaronesia, central Asia, and India (Anderberg 1991), and comprises ca. 500 (Hilliard 1983) to ca. 600 (Anderberg 1991) species. The only exhaustive infrageneric classification of the entire genus is that provided by de Candolle (1838). However, de Candolle’s classification did not always reflect natural phylogenetic relationships among species, and several more species have since been described. The Mediterranean, European, western Asian, and central Asian Helichrysum species are morphologically characterized as having the following characters: homogamous or heterogamous capitula, with hermaphroditic flowers outnumbering the pistillate ones; phyllaries with a fenestrated stereome; smooth or alveolate receptacle; cypselae glabrous or with duplex hairs; monomorphic uniseriate pappus, consisting of several free scabrid bristles, with patent cilia at the base. Our previous phylogenetic studies on this genus based on ITS sequences (Galbany-Casals et al. 2004a) showed this group to be monophyletic and deReceived 21 October 2005. Published on the NRC Research Press Web site at http://canjbot.nrc.ca on 12 September 2006. M. Galbany-Casals and C. Benedı́. Departament de Productes Naturals, Biologia Vegetal i Edafologia, Unitat de Botànica, Facultat de Farmàcia, Universitat de Barcelona, Avda. Joan XXIII s/n, E-08028 Barcelona, Spain. L. Sáez.1 Unitat de Botànica, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Facultat de Ciències, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona, Spain. 1Corresponding author (e-mail: llorens.saez@uab.es). Can. J. Bot. 84: 1203–1232 (2006) rived from African ancestors, findings supported by the fact that they constitute a rather uniform group with regards to the gross morphology of vegetative characters, as well as most of the reproductive character morphology. The only exception was that two species, Helichrysum frigidum (Labill.) Willd. and H. montelinasanum Schmid, appeared grouped with the outgroups in the phylogenetic tree obtained, not within the Mediterranean Helichrysum clade nor the main Helichrysum clade. Following a detailed study based on morphological traits, these two species were tranferred to a new genus, Castroviejoa Galbany, L. Sáez & Benedı́: Castroviejoa frigida (Labill.) Galbany, L. Sáez & Benedı́ and Castroviejoa montelinasana (Schmid) Galbany, L. Sáez & Benedı́ (Galbany-Casals et al. 2004b, 2004c). The Mediterranean, European, western Asian and central Asian Helichrysum species have been classified into two main groups (see Table 1 for main infrageneric classifications), which in the latest treatment (Clapham 1976) are recognised at the sectional level: Helichrysum sect. Helichrysum, mainly equivalent to de Candolle’s unranked group Stoechadina, and H. sect. Virginea (DC.) Gren. & Godr. In this treatment, species belonging to H. sect. Helichrysum are shrubs, sub-shrubs or herbaceous perennials, with capitula in terminal corymbose synflorescences, bearing yellow or rarely white phyllaries, nearly equalling the florets in length. Species in H. sect. Virginea are caespitose, suffruticose perennials, with capitula solitary or in terminal oligocephalous corymbose synflorescences, with white phyllaries extending beyond the florets. This paper stems from wider research on the systematics of the genus Helichrysum Mill. in the Mediterranean, European, western Asian, and central Asian regions, consisting of the species of the two sections cited above. Based on our re- doi:10.1139/B06-082 # 2006 NRC Canada 1204 Table 1. Major Helichrysum infrageneric classifications, showing the Mediterranean, Western Asiatic, and Central Asiatic species. de Candolle (1838) Grenier and Godron (1850) Bentham (1873) Sect. Euhelichrysum Ser. Argyraea DC. [unranked] Virginea DC. H. virgineum H. frigidum Sect. Virginea (DC.) Gren. & Godr. H. frigidum Subgenus Euhelichrysum Sect. Xerochlaena (DC.) F. Muell. H. frigidum H. virgineum Boissier (1875) Kirpicznikov (1959) Clapham (1976) Subgenus Helichrysum [unranked] Virginea DC. Sect. Virginea (DC.) Gren. & Godr. H. amorginum H. taenari H. sibthorpii H. doerfleri H. frigidum H. sibthorpii (as H. virgineum) H. amorginum H. virgineum (as H. billardieri) Ser. Argyraea DC. [unranked] Sphaerocephala DC. H.? sanguineum Ser. Chrysolepidea DC. [unranked] Stoechadina DC. Sect. Stoechadina (DC.) Gren. & Godr. Sect. Stoechas Benth. [unranked] Stoechadina DC. Sect. Helichrysum Sect. Helichrysum H. crassifolium (as H. lamarckii) H. arenarium European, Eastern Mediterranean, Asiatic, and North African species except H. frigidum and H. virgineum [unranked] Oligophylla Boiss. Ser. Arenaria Kirp. H. stoechas H. rupestre H. stoechas (+ H. decumbens) H. heldreichii H. arenarium H. stoechas (+ H. decumbens and H. caespitosum) H. angustifolium H. serotinum H. stoechas (as H. siculum) H. italicum (as H. angustifolium and H. microphyllum) H. orientale H. rubicundum (as H. undulatum) H. leucocephalum (as H. kopetdagense) H. thianschanicum H. rupestre (+ H. saxatile) H. crassifolium (as H. ambiguum) H. italicum H. pallasii H. armenium H. plicatum H. plicatum H. graveolens (as H. avandulaefolium) H. globiferum H. subsimile (as H. griffithii) H. noeanum # H. pallasii (as H. callichrysum) H. orientale H. graveolens (+ H. lavandulaefolium) H. arenarium (+ H. buchtormense) H. oligocephalum [unranked] Imbricata Boiss. 2006 NRC Canada H. sanguineum H. armenium (+ H. tchabanicum) H. italicum Ser. Mussaeana Kirp. H. angustifolium (as H. litoreum) H. orientale H. plicatum H. mussae H. nuratavicum H. arenarium H. graveolens Ser. Plicata Kirp. H. plicatum (+ H. polyphyllum) H. maracandicum H. graveolens Can. J. Bot. Vol. 84, 2006 H. italicum (as H. microphyllum) 1205 H. pamphylicum (as H. niveum) Ser. Callichrysa Kirp. H. pallasii (+ H. callichrysum and H. polylepis) H. aurantiacum Note: Names of taxa in brackets and preceded by ‘‘+’’ are those that appear in the cited treatment but that we consider as synonyms of the taxon they follow. de Candolle (1838) Table 1 (concluded). Grenier and Godron (1850) Bentham (1873) Boissier (1875) H. arenarium (+ H. aucheri) H. leucocephalum (+ H. oocephalum and H. buhseanum) H. artemisioides H. compactum Kirpicznikov (1959) Ser. Araxina Kirp. H. armenium (+ H. araxinum) Clapham (1976) Galbany-Casals et al. search, we split Helichrysum sect. Helichrysum into two sections based on morphological and molecular phylogenetic data: H. sect. Helichrysum and H. sect. Stoechadina. The species included in the former are mainly distributed across the eastern Mediterranean, Europe, and western Asia to central Asia, they are suffruticose, nearly all caespitose, and some of them stoloniferous or rhizomatous, with basal leaf rosettes generally subtending conspicuous resting buds. Some species have homogamous capitula and others heterogamous. With reference to chromosome number, some species are tetraploids (2n = 28) and others octoploids (2n = 56). The species included in H. sect. Stoechadina generally have a western and central Mediterranean distribution and consist of shrubs or sub-shrubs. They never possess conspicuous resting buds, nor stolons or rhizomes, and only H. crassifolium has basal rosettes. All exhibit heterogamous capitula. Concerning chromosome number, all species have 2n = 28. The recognition of this section based on morphology, particularly with regards to habit, seems to coincide with the trends observed in our ITS phylogenetic study (Galbany-Casals et al. 2004a). In the present paper, we provide a taxonomic revision of the species forming Helichrysum sect. Stoechadina. Our criteria for taxonomic delimitation in Helichrysum are based on the evaluation of discriminating morphological features, the relationships between morphological and geographical variation patterns, and the nature and extent of transitional forms, if any, linking discrete entities. Morphological attributes underlying the separation of taxa included in sect. Stoechadina are scant and this has sometimes generated confusion in plant identification. We encountered some difficulties in delimiting some species because of similar morphology and the phenotypic plasticity exhibited by the most widespread species, such as H. italicum, H. stoechas, and H. rupestre, which present complex patterns of continuous variation in several vegetative and reproductive features. Moreover, some of the morphological variation appears to stem from gene flow between species, since hybridization appears to be significant in Helichrysum (Jeanmonod 1996; GalbanyCasals et al. 2004a). In addition, a great number of taxa have been described at various taxonomic ranks, and most of these have then also been combined at other taxonomic ranks. We thus dealt with a great number of names, studied a significant percentage of the corresponding type specimens, and designated, when necessary and possible, a lectotype or neotype for them (Galbany-Casals et al. 2006). Two more type specimens are designated in the present revision. Under each taxon accepted in the present taxonomic treatment, only synonyms that appear in main floristic works are given. Materials and methods This revision is based on 3520 herbarium specimens, including type specimens, from the following herbaria: ARAN, B-W, BC, BCN, BM, C, COA, COI, COI-WILLK., E, FI, G, G-DC, G-BOIS, HJBS, Herb. Universitat Illes Balears, JACA, JAEN, K, LINN, LISU, LY, MA, MGC, MPU, NAP, P, PAL, PH, PO, SANT, SASSA, SEV, TO, UPSBURSER, VAL, W, and WU. The number of studied specimens for each taxon depended on the extent of its distribu# 2006 NRC Canada 1206 tional area and on the taxonomic difficulties involved. In addition, specimens of several species were observed and collected in the wild (see supplementary data2). Morphology All morphological data presented in the Results and discussion section and used in the description of taxa were directly observed by the authors. We studied the morphological characters traditionally used in floristic or taxonomic treatments and other morphological characters of interest found during our research. For all studied characters an evaluation of their individual taxonomic value was made, and all were subsequently incorporated into taxon descriptions. Features of gross morphology were studied under a Zeiss binocular stereoscopic microscope. For every quantitative character of leaves, synflorescence, capitula, phyllaries, and florets, at least three measurements or counts were taken for each specimen, and for a variable number of specimens per taxon (see Table 2 for total measurements of each taxon). Some of the quantitative characters were also used in statistical analysis; we performed comparison of means tests (t statistic) for characters used in the literature to distinguish pairs of taxa with the aim of demonstrating if mean taxon values are significatively different and useful to distinguish the pairs of taxa involved (see Statistical analysis section and Table 3). Features of micromorphology were studied in several specimens of each taxon. Samples of leaf and phyllary indumentum were placed on microscope slides and observed under a Nikon Eclipse E-400 optical microscope or occasionally glued to aluminium stubs, coated with 50 nm gold, and examined with a Hitachi-2300S scanning electron microscope (SEM) at 10–15 kV. The cleared preparations of dissected florets were made by placing them in a commercial solution of sodium hypochlorite until they were transparent (Stace 1965). A Nikon Eclipse E-400 optical microscope was used to examine the corolla indumentum and veins, stamen morphology, endothecial tissue type, and the pappus bristle structure. Phyllaries were cleared as above to examine the stereome under a Nikon Eclipse E-400 optical microscope. For SEM studies, samples of styles, cypselae, and pappus were glued to aluminium stubs, coated with 50 nm gold and examined with a Hitachi-2300S SEM at 10– 15 kV. Cypselae were placed in water for 1–4 h to determine if duplex hairs were myxogenic. When duplex hairs are myxogenic the mucilage secreted through the tip of each duplex hair can be easily observed under an optical microscope. Throughout this study we use the terminology for morphological features used by Hilliard and Burtt (1981a), unless otherwise indicated. In all measurements, we indicate minimum and maximum length values followed by minimum and maximum width values. Numbers in brackets indicate extreme values. Distribution, altitudinal range and ecology For each studied taxon, as well as for intermediate specimens between several pairs of taxa, a distribution map was Can. J. Bot. Vol. 84, 2006 prepared based exclusively on herbarium specimens to avoid potentially misleading data. Specimens represented on the map are marked with an asterisk in the list of representative material examined2. The complete list of specimens represented on the maps are available by request from the authors. Information on ecology and altitudinal range comes from information on the labels and from personal field observations. Results and discussion Taxonomic characters General habit All species are shrubby or sub-shrubby perennials, arachnoid to densely tomentose. They possess several vegetative stems, which are erect, ascendent, or decumbent, and leafy throughout their length. Helichrysum italicum subsp. microphyllum and H. italicum subsp. siculum nearly always bear axillary leaf fascicles on the vegetative stems (Fig. 8B). The fascicles are short, densely leaved little branches that do not elongate but persist as axillary to adult leaves. These axillary leaf fascicles are not found in other taxa, except rarely in some specimens of H. serotinum and H. italicum subsp. italicum. Helichrysum crassifolium is the sole species with leaf rosettes arising terminally on thick woody erect stems, branching from the woody caudex. All species have several flowering stems, which are erect, ascendent or decument, and leafy throughout their length, more densely in the basal part. Leaves All species have alternate leaves, which are sessile and subdecurrent on the stem. Basal leaves on the flowering stems are patent to erecto-patent, except in H. rupestre, H. errerae, and H. heldreichii, which have basal leaves reflexed and medial leaves patent to erecto-patent. Leaves decrease in size to the synflorescence in all species’ flowering stems, with uppermost leaves becoming appressed to the stem and more laxly arranged. Leaf shape is rather fixed for some taxa; for example, leaves of H. angustifolium, H. heldreichii, H. italicum, and H. serotinum are always linear, leaves of H. errerae are always oblanceolate to narrowly spathulate, and leaves of H. crassifolium are always obovate to broadly spathulate. In some taxa, however, leaf shape can be very variable; for example, leaves of H. rupestre and H. stoechas can be linear, lanceolate, oblanceolate, or spathulate. Leaf margins can be, on the one hand, flat or revolute, and on the other hand, undulate or not undulate. The combination of these two characters is sometimes useful in distinguishing some closely related taxa, although in other cases this proves to be too variable and unhelpful. For example, leaves of H. crassifolium and H. errerae nearly always exhibit flat margins lacking undulation. Leaves of H. angustifolium, H. heldreichii, and H. serotinum nearly always exhibit revolute margins lacking undulation. Leaves of the three subspecies of H. italicum always have revolute 2 Supplementary data for this article are available on the journal Web site (http://canjbot.nrc.ca) or may be purchased from the Depository of Unpublished Data, Document Delivery, CISTI, National Research Council Canada, Building M-55, 1200 Montreal Road, Ottawa, ON K1A 0R6, Canada. DUD 5069. For more information on obtaining material refer to http://cisti-icist.nrc-cnrc.gc.ca/irm/unpub_e.shtml. # 2006 NRC Canada Galbany-Casals et al. margins, but those of H. italicum subsp. microphyllum are usually undulate and this character differs from the other two subspecies. Finally, leaves of H. stoechas and H. rupestre always lack undulate margins, although both can be revolute or flat. Indumentum Trichomes found on stems, leaves and phyllaries are of two major types. The first corresponds to hair-type ‘‘B’’ of Drury and Watson (1966), which are multicellular uniseriate hairs and consist of one to five short basal cells and a very long terminal cell (Fig. 1A). This type of trichome is found on stems, on both surfaces of leaves, and on phyllaries of all taxa. Leaves can be glabrate to tomentose according to the density of this trichome type. The abaxial surface of leaves is always tomentose for all taxa. The adaxial surface of leaves is variable with regards to indumentum density and leaves can be concolorous, if they are adaxially and abaxially tomentose, or discolorous if they are adaxially glabrate to arachnoid-tomentose and abaxially tomentose. Phyllaries can also have a variable density of these trichomes, but this character is particularly important in the case of the outermost phyllaries, as previously reported in several studies (Clapham 1976; Devesa 1987; Bolòs and Vigo 1996), as it is stable for each species. The second type is a multicellular biseriate glandular hair, 46–120 mm long (Fig. 1B). The essential oils contained in this type of trichome makes these species slightly aromatic (Ascensão et al. 2001). Secretory products accumulate in a subcuticular space or secretory cavity above the upper part of the apical pair of cells (Afolayan and Meyer 1995). For detailed morphology and ultrastructure of multicellular biseriate secreting trichomes, see Afolayan and Meyer (1995). These hairs are present on the outside of the corolla lobes, on the abaxial surface of leaves and on phyllaries of nearly all species, but in varying density. Thus, concerning the density of these glandular hairs, the leaf abaxial surface and phyllaries range from eglandular to densely glandular. Although this density is rather variable in each species, some trends can be observed that contribute to species characterization. This type of multicellular biseriate glandular hair is also present on the cypselae surface of some specimens of Helichrysum italicum subsp. microphyllum, mixed with duplex hairs (see below) (Fig. 1C). Although this type of hair is rather common on the cypsela surfaces of several species of H. sect. Helichrysum (M. Galbany-Casals, personal observation), it was never reported before in any species of H. sect. Stoechadina. Most species have elongate, spreading when wet and myxogenic, white duplex hairs, which are regularly arranged on the cypsela surface. This type of hair consists of two elongate, parallel cells and a third basal cell (Hess 1938) (Fig. 1D). The duplex hairs are present on the cypselae of H. angustifolium, H. crassifolium, H. errerae, H. heldreichii, H. italicum, H. rupestre, and H. stoechas, although some specimens of H. stoechas and H. italicum subsp. microphyllum may have glabrous cypselae. When present, duplex hairs are very similar in shape and length among the different studied species, the length varying from 30 to 46 mm. Helichrysum serotinum always has glabrous cypselae, without duplex hairs. 1207 Capitula In all species, capitula are grouped in terminal corymbose synflorescences, which can be dense to rather lax and branched. Capitula are heterogamous, with hermaphroditic flowers outnumbering the pistillate ones, although homogamous capitula have been found in one specimen of H. italicum subsp. microphyllum and in several specimens of both subspecies of H. serotinum. Capitula shape is important in species characterization, as has already been stated (Quezel and Santa 1963; Rechinger 1973; Clapham 1976; Pignatti 1982; Bolòs and Vigo 1996; Jeanmonod 1998): H. angustifolium, H. heldreichii, H. italicum, and H. serotinum have cylindrical to narrowly campanulate capitula; H. crassifolium has campanulate capitula; and H. errerae, H. rupestre and H. stoechas have broadly campanulate to hemispherical capitula (Fig. 2). The shape is partly represented by the ratio capitula length/capitula width (see Table 2). Receptacle The receptacle is naked in all species and usually flat, although it may sometimes be concave or rarely convex. The surface may be smooth, without any conspicuous alveolae, or alveolate, with the alveolae irregularly dentate, the teeth not exceeding the ovary in length (Fig. 3A). Receptacle features can vary within a species and do not impart any taxonomic value. Phyllaries Phyllaries are always imbricate in several rows, densely arranged in H. angustifolium, H. crassifolium, H. italicum, and H. serotinum and laxly arranged in H. errerae, H. heldreichii, H. rupestre, and H. stoechas. The outermost ones may be completely papery, completely coriaceous, or coriaceous in the proximal half and papery in the distal half. This character completely correlates with the indumentum density of the outermost phyllaries. Consequently, the outermost phyllaries are completely papery and glabrous, or have only some hairs at the base, or they are coriaceous and tomentose on their proximal half, or they are completely coriaceous and completely tomentose. Medial and innermost phyllaries of all species have a proximal stereome and a distal papery yellow lamina. The phyllary series for all taxa are shown in Fig. 4. Drury (1970) was the first to describe the distinct structures of the basal coriaceous part of the phyllary, known as the stereome. In the genus the stereome can be undivided, when it appears continuously opaque due to the sclerenchymatous wall thickenings of all cell walls, or fenestrated, when it appears with a transparent patch caused by inner cells with unthickened walls. All species of H. sect. Stoechadina have a fenestrated stereome. Phyllaries of the middle series are approximately of the same length as the innermost ones (see Table 2). This ratio is merely descriptive within H. sect. Stoechadina, but it is helpful in distinguishing species of this section from species of H. sect. Virginea (M. Galbany-Casals, personal observation). A taxonomic revision of H. sect. Virginea and H. sect. Helichrysum is in preparation by the authors of the present paper, in which the importance of this character for section delimitation is demonstrated. # 2006 NRC Canada 1208 Can. J. Bot. Vol. 84, 2006 Table 2. Minimum, maximum, and mean values, and standard deviation for the most significant measured morphological characters. Characters: X ± SD (Min. – Max.) (N) Taxa H. angustifolium H. crassifolium H. errerae H. heldreichii H. italicum subsp. siculum H. italicum subsp. italicum H. italicum subsp. microphyllum H. rupestre H. serotinum subsp. picardii H. serotinum subsp. serotinum H. stoechas Leaf L (mm) 46.80±11.13 (19–80) (N = 75) 36.79±11.39 (14–85) (N = 390) 40.04±8.88 (23–58) (N = 25) 39.25±8.29 (29–60) (N = 20) 11.20±3.94 (7–21) (N = 10) 20.84±6.69 (7–37) (N = 140) 8.64±4.52 (2–29) (N = 185) 46.65±18.29 (13–95) (N = 380) 25.31±9.53 (10–55) (N = 215) 30.10±9.48 (12–57) (N = 230) 15.31±7.35 (4–45) (N = 495) Leaf W (mm) 1.23±0.30 (0.8–2) (N = 75) 7.80±2.43 (3.5–19) (N = 390) 3.60±1.53 (1.5–8) (N = 25) 3.03±1.53 (1–5) (N = 20) 0.87±0.15 (0.6–1) (N = 10) 0.87±0.17 (0.4–1.8) (N = 140) 0.93±0.19 (0.5–1.5) (N = 185) 2.84±1.20 (1–8.5) (N = 380) 1.02±0.25 (0.5–2) (N = 215) 0.96±0.22 (0.5–2) (N = 230) 1.12±0.63 (0.4–7) (N = 495) Leaf L / Leaf W 39.59±10.60 (14.62–60.00) (N = 75) 4.93±1.45 (1.71–10.75) (N = 390) 12.35±4.27 (5.62–28.00) (N = 25) 16.53±8.67 (6.40–37.00) (N = 20) 12.98±4.10 (9.00–21.00) (N = 10) 24.82±9.25 (7.00–51.67) (N = 140) 9.38±4.43 (2.00–29.00) (N = 185) 18.13±8.51 (4.33–60.00) (N = 380) 25.27±8.65 (10.83–50.00) (N = 215) 32.26±10.35 (12.00–65.00) (N = 230) 15.72±9.05 (1.43–68.00) (N = 495) Cap / Synfl 98.33±66.09 (34–306) (N = 30) 50.35±23.82 (13–130) (N = 80) 47.92±20.25 (24–103) (N = 13) 67.50±59.02 (30–211) (N = 8) 17.50±14.47 (3–42) (N = 6) 41.68±25.29 (10–120) (N = 81) 17.20±12.22 (1–64) (N = 110) 47.21±29.91 (7–152) (N = 171) 58.66±40.32 (7–252) (N = 115) 43.55±27.88 (9–146) (N = 127) 16.08±8.52 (3–72) (N = 296) Cap L (mm) 4.87±0.46 (4–6) (N = 75) 5.52±0.56 (4–7.5) (N = 350) 5.18±0.45 (4.5–6) (N = 25) 4.33±0.36 (4–5) (N = 15) 4.85±0.67 (4–6) (N = 10) 4.96±0.50 (4–6.5) (N = 140) 5.12±0.50 (4–6.5) (N = 185) 5.96±0.77 (4–8) (N = 350) 5.22±0.58 (4–6.5) (N = 205) 5.70±0.54 (4.5–7.5) (N = 230) 5.58±0.65 (4–8) (N = 480) Cap W (mm) 3.75±0.41 (2.5–4.5) (N = 75) 4.87±0.58 (3.5–6) (N = 350) 5.48±0.74 (4.5–7) (N = 25) 2.77±0.32 (2–3) (N = 15) 3.50±0.47 (3–4) (N = 10) 3.08±0.31 (2.5–4) (N = 140) 3.25±0.52 (2–5) (N = 185) 6.10±0.88 (4–8) (N = 350) 2.95±0.51 (2–4.5) (N = 205) 3.39±0.44 (2.5–5) (N = 230) 5.70±0.79 (4–8) (N = 480) Note: Cap, capitula; Fl, hermaphroditic florets; Inn IB, innermost phyllaries; L, length; max., maximum value; med IB, medial phyllaries; Min., minimum values of each character for each measured specimen, then N is the number of specimens. In those cases, when possible, Fl L, Inn IB L, and Out IB L Florets The corolla is yellow in all species. The corolla of pistillate florets is narrowly tubular while that of hermaphroditic florets is also tubular, but widened in its upper part; corolla lobes are triangular, acute, becoming reflexed at anthesis, with the veins reaching the lobe apices. Florets are more or less of the same length as the medial and innermost phyllaries (see Table 2). This ratio is merely descriptive within H. sect. Stoechadina, although it is helpful in distinguishing species of this section from species of H. sect. Virginea (M. Galbany-Casals, personal observation). A taxonomic revision of H. sect. Virginea and H. sect. Helichrysum is in preparation by the authors of the present paper, in which the importance of this character for section delimitation is shown. Stamens All species have ecalcarate stamens, that is, the filament is inserted at the base of the thecae and the fertile polliniferous part of the anther does not protrude below the insertion point. The thecae are 1000–1200 mm long. The thecae present short and branched, sterile basal appendages of 200–460 mm long. The anthers have a flat, lanceolate, obtuse sterile apical appendage of 200–320 mm long, and are as wide as the thecae or slightly narrower. All species have polarized endothecial tissue, that is, the thickenings are confined to horizontal walls. Style The same structure is common to all species: bifid, with the style branches truncate and presenting obtuse sweeping hairs only apically (Fig. 3B); stigmatic surfaces are separated in two lines. Cypselae These are cylindrical to ovoid-cylindrical and very similar in all species. The epidermis is smooth and glabrous or has regularly arranged duplex hairs (Figs. 3C, 3D). Pappus The pappus is monomorphic in all species and consists of one row of free bristles or setae. All species have bristles with basal patent cilia. The shaft is scabrid in all species. Apical cells are obtuse in H. angustifolium, H. errerae, # 2006 NRC Canada Galbany-Casals et al. Cap L / Cap W 1.31±0.13 (1–1.8) (N = 75) 1.14±0.13 (0.80–1.50) (N = 350) 0.95±0.07 (0.83–1.1) (N = 25) 1.58±0.17 (1.33–2) (N = 15) 1.39±0.15 (1.14–1.67) (N = 10) 1.62±0.18 (1.25–2.00) (N = 140) 1.60±0.21 (1.10–2.20) (N = 185) 0.99±0.12 (0.67–1.37) (N = 350) 1.80±0.24 (1.25–2.75) (N = 205) 1.70±0.21 (1.12–2.20) (N = 230) 0.99±0.10 (0.75–1.37) (N = 480) Fl / Cap 26.75±3.21 (15–31) (N = 36) 41.96±9.64 (20–68) (N = 90) 32.92±5.66 (24–40) (N = 12) 15.25±8.54 (17–37) (N = 4) 18.80±3.27 (15–23) (N = 5) 21.68±4.44 (13–34) (N = 82) 19.26±4.13 (8–31) (N = 109) 46.02±13.06 (20–88) (N = 169) 14.87±4.19 (7–26) (N = 123) 22.86±4.13 (14–36) (N = 137) 40.22±10.01 (21–75) (N = 276) 1209 Out IB L (mm) 1.71±0.22 (1.30–2) (N = 75) 2.48±0.36 (1.9–3.3) (N = 330) 3.05±0.30 (2.5–3.9) (N = 25) 2.07±0.15 (1.9–2.5) (N = 18) 1.16±0.15 (1–1.5) (N = 10) 1.51±0.36 (1–3) (N = 140) 1.78±0.29 (1–2.5) (N = 185) 3.48±0.67 (1.9–5) (N = 360) 1.82±0.40 (0.8–2.9) (N = 205) 1.78±0.36 (1–3) (N = 227) 3.35±0.61 (2–5.5) (N = 485) Out IB W (mm) 1.03±0.23 (0.6–1.8) (N = 75) 1.77±0.23 (1.2–2.5) (N = 330) 1.56±0.27 (0.9–2) (N = 25) 0.74±0.25 (0.4–1.2) (N = 18) 0.69±0.20 (0.4–0.9) (N = 10) 0.89±0.21 (0.4–1.5) (N = 140) 0.78±0.14 (0.4–1.2) (N = 185) 2.19±0.36 (1.3–3.2) (N = 360) 0.82±0.16 (0.5–1.2) (N = 205) 0.83±0.17 (0.4–1.4) (N = 227) 2.10±0.36 (1–3) (N = 485) Inn IB L / Out IB L* 2.33±0.28 (2.01–2.80) (N = 10) 1.72±0.20 (1.41–2.00) (N = 13) 1.34±0.10 (1.21–1.45) (N = 5) 1.89±0.01 (1.88–1.89) (N = 3) 3.31±0.02 (3.30–3.32) (N = 2) 2.87±0.47 (1.92–3.64) (N = 26) 2.47±0.40 (1.86–3.45) (N = 36) 1.36±0.25 (1.01–2.09) (N = 47) 2.32±0.44 (1.47–3.67) (N = 38) 2.54±0.53 (1.63–3.73) (N = 32) 1.38±0.21 (0.97–1.95) (N = 52) Inn IB L / Med IB L* 1.05±0.03 (1.02–1.10) (N = 10) 1.07±0.04 (1.02–1.14) (N = 13) 1.07±0.06 (1.03–1.16) (N = 5) 1.07±0.07 (0.99–1.13) (N = 3) 1.06±0.08 (1.00–1.12) (N = 2) 1.05±0.05 (0.96–1.19) (N = 26) 1.09±0.06 (0.99–1.21) (N = 36) 1.08±0.06 (0.96–1.21) (N = 47) 1.06±0.06 (0.96–1.19) (N = 38) 1.03±0.04 (0.97–1.13) (N = 32) 1.04±0.04 (0.93–1.18) (N = 52) Med IB L / Fl L* 1.08±0.07 (1.00–1.18) (N = 10) 1.05±0.10 (0.88–1.19) (N = 13) 1.08±0.03 (1.06–1.11) (N = 4) 1.22±0.16 (1.11–1.33) (N = 2) 1.13±0.02 (1.11–1.14) (N = 2) 1.10±0.08 (0.95–1.28) (N = 26) 1.09±0.11 (0.87–1.32) (N = 36) 1.09±0.09 (0.91–1.27) (N = 47) 1.02±0.07 (0.89–1.20) (N = 38) 1.08±0.09 (0.89–1.27) (N = 32) 1.13±0.09 (0.92–1.34) (N = 52) value; N, number of measurements; Out IB, outermost phyllaries; Synfl, synflorescence; X, mean; W, width. *These ratios are calculated from mean correspond to a mean of five measurements per specimen, while Med IB L is one measurement per specimen. H. rupestre, H. serotinum and H. stoechas; acute in H. heldreichii and H. italicum; and acute to obtuse in H. crassifolium (Figs. 3E, 3F). Statistical analysis During our taxonomic work we realized that qualitative characters permitting species identification are scarce in the genus Helichrysum, making differentiation of closely related species frequently difficult. Some groups of very closely related taxa do not have unique and distinctive qualitative traits and thus it is necessary to use quantitative characters. A summary of the most useful traits of all studied quantitative characters is shown in Table 2. Some of these quantitative characters have partly overlapping ranges of values among several taxa, but they have been often used in floristic treatments for differentiation of certain pairs of taxa. We conducted comparison of means tests (t tests) for those characters that appear to distinguish certain pairs of taxa in the literature. In this way we could determine whether mean taxon values are significantly different and useful for distinguishing the involved pairs of taxa. t tests were performed using the individual mean value for each character and taxon, thereby ruling out pseudoreplication. Before each comparison of means, normal distribution of the data and variances homogeneity were tested. All variables had a normal distribution. In some cases there was no variance homogeneity, and then it is indicated in Table 3. Although other studied quantitative characters are not commented upon, they were all used in taxa descriptions. Leaf length varies considerably in all species with ranges often overlapping among different taxa. However, it remains a very useful character for distinguishing certain pairs of taxa that lack any other distinctive feature: For example, it is useful to distinguish the Sicilian specimens of H. italicum from the remaining specimens of H. italicum subsp. italicum (see Table 3). These Sicilian specimens were recognised at the species level as H. siculum by Jordan and Fourreau (1868). Here we propose the combination at subspecies level of H. italicum based on several quantitative and qualitative traits (see Taxonomic treatment section). Clapham (1976) also used leaf length to distinguish two subspecies of H. stoechas: H. stoechas subsp. stoechas and H. stoechas subsp. barrelieri (Ten.) Nyman. He stated that H. stoechas subsp. stoechas grows from western Croatia # 2006 NRC Canada 1210 Can. J. Bot. Vol. 84, 2006 Table 3. Comparison of the means test (t tests) results. Character Leaf length Leaf length Leaf length Leaf length Leaf length Innermost phyllaries length / outermost phyllaries length Innermost phyllaries Innermost phyllaries Innermost phyllaries Innermost phyllaries Innermost phyllaries Innermost phyllaries Innermost phyllaries Total no. of florets / Capitula length Capitula width length / outermost length / outermost length / outermost length / outermost length / outermost length / outermost length / outermost capitula phyllaries phyllaries phyllaries phyllaries phyllaries phyllaries phyllaries length length length length length length length Taxa H. stoechas subsp. barrelieri vs. H. stoechas subsp. stoechas H. stoechas vs. H. rupestrea H. italicum subsp. italicum vs. H. angustifolium H. italicum subsp. italicum vs. H. italicum subsp. microphyllum H. italicum subsp. italicum vs. H. italicum subsp. siculum H. stoechas subsp. barrelieri vs. H. stoechas subsp. stoechas H. stoechas vs. H. rupestre H. rupestre vs. H. italicuma H. rupestre vs. H. serotinuma H. rupestre vs. H. angustifolium H. stoechas vs. H. italicuma H. stoechas vs. H. serotinuma H. stoechas vs. H. angustifolium H. serotinum vs. H. picardii H. serotinum vs. H. picardii H. serotinum vs. H. picardii t –0.8247 P 0.4135 –13.6563 –10.2881 –10.0262 0.0000* 0.0000* 0.0000* –5.2020 0.0000* –1.9186 0.0607 0.4708 –16.7183 13.6627 –10.9542 –17.6850 –14.2433 –12.0635 –9.0756 –4.3370 –4.7152 0.6389 0.0000* 0.0000* 0.0000* 0.0000* 0.0000* 0.0000* 0.0000* 0.0000* 0.0000* Note: *, statistical significance at P < 0.05. Non-homogeneity of variances. a westwards and has longer leaves than those of H. stoechas subsp. barrelieri, which grows from Sicily eastwards. We conducted a comparison of means test to determine any significant differences in this character between western and eastern Mediterranean specimens of H. stoechas, and found that they do not differ in leaf length (results are shown in Table 3). We also used comparison of means test to identify differences in leaf length among other pairs of taxa, finding significant differences for all them (see results in Table 3). Clapham (1976) also used the ratio innermost phyllaries / outermost phyllaries to distinguish the two subspecies within H. stoechas; he stated that H. stoechas subsp. stoechas has innermost phyllaries at least three times as long as the outermost ones, and H. stoechas subsp. barrelieri has innermost phyllaries rarely more than twice as long as the outermost ones. We therefore performed a comparison of means test to again gauge any significant differences in this character between western Mediterranean and eastern Mediterranean specimens of H. stoechas, finding that they do not differ in this ratio (results are shown in Table 3). Minimum, maximum, and mean values of this character for H. stoechas are shown in Table 2. Other authors (Clapham 1976; Bolòs and Vigo 1996) have used the same ratio innermost phyllaries / outermost phyllaries to separate other closely related pairs of taxa. We performed comparison of means tests to verify any significant differences in this character for the taxa involved. Results are shown in Table 3. Capitula size, both length and width, and the number of florets per capitula, are particularly useful to distinguish H. serotinum and H. picardii, as Devesa (1987) already stated. We again employed comparison of means test to determine any significant differences in these three characters between these two taxa, and did indeed find this to be the case for all three of the characters (Table 3). Taxonomic treatment Helichrysum sect. Stoechadina (DC.) Gren. & Godr., Fl. Fr. 2: 183 (1850) : H. [unranked] Stoechadina DC., Prodr. 6: 181 (1838). H. stoechas (L.) Moench. Shrubby or sub-shrubby perennials, arachnoid to densely tomentose. Several vegetative stems, erect, ascendent or decumbent, leafy all their length, sometimes bearing axillary leaf fascicles (rosettes of leaves present in one species); several flowering stems, erect, ascendent or decument, leafy all their length, more densely so basally. Synflorescence corymbose, terminal, dense to rather lax and branched. Capitula heterogamous rarely homogamous, with the hermaphroditic florets more numerous than the pistillate ones. Phyllaries erect, flat, approximately as long as the florets (ratio of the mean length of middle phyllaries / mean length of hermaphroditic florets 0.87–1.34), densely or laxly imbricate, yellow, papery (except the outermost ones in some species); stereome fenestrated. Middle phyllaries approximately as long as the innermost ones, ratio of the mean length of innermost phyllaries / mean length of the middle phyllaries 0.93–1.21. Receptacle naked, smooth or alveolate, alveolae irregularly dentate, not exceeding the ovary in length. Corolla of the pistillate florets tubular; corolla of the hermaphroditic florets tubular, campanulate above. Cypselae cylindrical to ovoid-cylindrical; epidermis smooth. Pappus of free scabrid capillary bristles, white, basally with patent cilia. Pollen grains spinulose, with double sexine: the outer layer baculate, the basal layer compact and regularly perforated. 2n = 28. TYPE (ART. 22.6): DESCRIPTION: # 2006 NRC Canada Galbany-Casals et al. 1211 Fig. 1. Different types of trichomes in Helichrysum sect. Stoechadina. (A) Multicellular uniseriate hairs (hair-type B) on leaf [H. rupestre, L. Sáez s.n. (BCN 6118)]. (B) Multicellular biseriate glandular hairs on phyllary [H. italicum subsp. microphyllum, M. Galbany & L. Sáez s.n. (BCN 6115)]. (C) Multicellular biseriate glandular hairs on cypsela of H. italicum subsp. microphyllum [L. Sáez 5739 (BCN 20710)]. (D) Duplex hair on cypsela surface [H. rupestre, M. Galbany & L. Sáez s.n. (BCN 20721)]. Scale bar = 100 mm for Figs. 1A and 1C; Scale bar = 50 mm for Figs. 1B and 1D. Key to the species 1. Plants with basal leaf rosettes; basal leaves (3.5)6–19 mm wide, oblanceolate to spathulate, subcrassiolate 1. H. crassifolium 1. Plants without basal leaf rosettes; basal cauline leaves 0.4–8.5 mm wide, linear, lanceolate or oblanceolate, slightly coriaceous .............................................................................. 2 2. Capitula 4–8 mm wide in its medial part, broadly campanulate to hemispherical . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Capitula 2–5 mm wide in its medial part, cylindrical to narrowly campanulate . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Outermost phyllaries coriaceous and completely covered with dense indumentum, or at least in their proximal part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4. H. errerae 3. Outermost phyllaries papery and glabrous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Plants generally shorter than 40 cm, generally aromatic, erect, ascendent or decumbent; leaves 4–30(45)  0.4–3(7) mm; capitula 4–6.5(8)  4–6.5(8) mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. H. stoechas 4. Plants generally taller than 50 cm, not aromatic, erect; leaves (13)30–95  (1)2–8.5 mm; capitula (4)5–8  (4)5–8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. H. rupestre 5. Lower cauline leaves of flowering stems reflexed; capitula 4–5  2–3 mm; phyllaries laxly imbricate, the outermost with the proximal half coriaceous and tomentose and the distal half papery and glabrous . . . . . . . . . . . . . . 5. H. heldreichii 5. Lower cauline leaves of flowering stems patent to erecto-patent; capitula 4–7.5  2–5 mm; phyllaries densely imbricate, the outermost generally completely coriaceous and tomentose, sometimes with the proximal half coriaceous and tomentose and the distal half papery and glabrous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6. Plants up to 80 cm high, not aromatic; leaves (19)28–80 mm long, eglandular to sparsely glandular on the abaxial surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. angustifolium 6. Plants up to 60 cm high, generally shorter than 50 cm, strongly aromatic; leaves 2–57 mm long, generally sparsely to densely glandular on the abaxial surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7. Leaves 2–37 mm long; cypselae epidermis with regularly scattered white duplex hairs; pappus bristles with apical cells acute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. italicum 7. Leaves 10–57 mm long; cypselae epidermis without duplex hairs; pappus bristles with apical cells obtuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. serotinum # 2006 NRC Canada 1212 Can. J. Bot. Vol. 84, 2006 Fig. 2. Capitula in Helichrysum sect. Stoechadina, drawn as pressed. (A) H. crassifolium [C. Benedı́ s.n. (BCN 25247)]. (B) H. stoechas [Blanco & M. Galbany s.n. (BCN 25245)]. (C) H. rupestre [Sáez s.n. (BCN 20719)]. (D). H. errerae [Italy, insula Pantellaria, 1855, E. & A. Huet du Pavillon s.n. (G)]. (E) H. angustifolium [Pellanda s.n. (MA 125197)]. (F) H. heldreichii [Rechinger fil. 13792 (W 12974)]. (G) H. italicum subsp. siculum [M. Galbany s.n. (BCN 24030)]. (H) H. serotinum subsp. picardii [Garcı́a Martı́nez s.n. (SANT 12448)]. (I) H. italicum subsp. microphyllum [Italy, Sardinia, arrondissement de Tempio, 2-VII-1882, Reverchon s.n. (Plantes de Sardaigne 96) (G)]. (J) H. serotinum subsp. serotinum [M. Galbany s.n. (BCN 25233)]. (K) H. italicum subsp. italicum [Fiori s.n. (Flora Italica exsiccata ser. III, No. 2570) (WU)]. Scale bar = 2 mm. # 2006 NRC Canada Galbany-Casals et al. 1213 Fig. 3. Micromorphologic features in Helichrysum sect. Stoechadina. (A) Receptacle surface [H. rupestre, Cardona s.n. & al. (BC 644521)]. (B) Tips of stigmatic branches [H. italicum subsp. microphyllum, G. Nieto 4529 & J. Fuertes (BCN 20718)]. (C) Cypselae with duplex hairs [H. rupestre, M. Galbany & L. Sáez s.n. (BCN 20721)]. (D) Glabrous cypselae [H. serotinum subsp. serotinum, Blanco & al. s.n. (BCN 20889)]. (E) Pappus bristle apex with rounded cells [H. errerae, Coll s.n. (H. Ross Herbarium Siculum 244) (G)]. (F) Pappus bristle apex with acute cells [H. heldreichii, Rechinger fil. 13792 (W 12974)]. Scale bar = 500 mm for Figs. 3A, 3C, and 3D; Scale bar = 100 mm for Figs. 3B, 3E, and 3F. Helichrysum crassifolium (L.) D. Don in Loudon, Hort. Brit.: 341 (1830) ILLUSTRATION: Cambessèdes (1827, Table 7, Pl. 17 [sub. H. lamarckii]). : Gnaphalium crassifolium L., Mant. Pl.: 112 (1767). DESCRIPTION: Suffruticose to fruticose perennials, densely tomentose, not aromatic, up to 60 cm high. Basal leaves of vegetative stems forming rosettes arising terminal on thick, woody, erect stems, branched from the woody caudex; several flowering stems, ascendent to erect, leafy all their length, more densely so basally. Rosette leaves 14–85 mm  (3.5)6–19 mm, obovate to broadly spathulate, subcrassiolate, petiolate, obtuse to completely rounded, concolorous, densely tomentose, LECTOTYPE: (Hilliard and Burtt 1973, p. 345) Cult. in horto upsaliensi (LINN 989: 27!). H. ambiguum auct., non (Pers.) C. Presl, Fl. Sicul. 1: 29 (1826). H. lamarckii auct., non Cambess. in Mém. Mus. Hist. Nat. 14: 269, t. 7 (1827). # 2006 NRC Canada 1214 eglandular on both surfaces, margin flat, not undulate. Leaves of the flowering stems subcrassiolate, sessile, subdecurrent, concolorous, densely tomentose and densely glandular on both surfaces, margin flat, not undulate; lower and medial cauline leaves obovate to spathulate, obtuse, patent to erecto-patent, decreasing in size to the synflorescence; uppermost cauline leaves linear, acute, appressed to the stem and laxly arranged. Synflorescences corymbose, terminal, dense to rather lax and branched, 12–80 mm  20–80 mm, with 13–130 capitula. Capitula 4–7.5 mm  3.5–6 mm, campanulate (Fig. 2A), heterogamous, with 20–68 yellow florets; pistillate florets 4–21, hermaphroditic florets 15–50. Phyllaries 23–46, densely imbricate, papery; outermost phyllaries 1.9–3.3 mm  1.2– 2.5 mm, totally papery, ovate or elliptic, acute or obtuse, subglabrous and eglandular at the base; middle phyllaries 2.5– 4.6 mm  2–3.1 mm, oblanceolate to broadly ovate, obtuse, stereome arachnoid and eglandular; innermost phyllaries 3.8–5.2 mm  0.5–1.7 mm, linear, narrowly lanceolate or narrowly oblanceolate, acute or obtuse, stereome glabrous to arachnoid, and eglandular; mean length of innermost phyllaries / mean length of outermost phyllaries 1.41–2.00; mean length of innermost phyllaries / mean length of middle phyllaries 1.02–1.14. (Fig. 4A). Receptacles flat, smooth or alveolate. Corolla of the pistillate florets 2.7–3.9 mm; corolla of the hermaphroditic florets 3.2–4.5 mm. Middle phyllaries length / mean length of the hermaphroditic florets 0.88–1.19. Cypselae 0.7–1.1  0.2–0.6 mm, cylindrical to ovoid-cylindrical, with regularly scattered white duplex hairs. Pappus bristles 2.4–4.2 mm long; apical cells acute to obtuse. CHROMOSOME NUMBER: 2n = 28 (Guinochet and Lefranc 1972). DISTRIBUTION: Endemic to the Balearic islands of Majorca, Dragonera, and Minorca (Fig. 5). HABITAT: Chasmophytic, on limestone vertical rock crevices. Altitudinal range: 20–1430 m. PHENOLOGY: Flowers (March) May–July. VARIABILITY: This species exhibits some variability in leaf shape and width; although leaves are in general broadly spathulate, some specimens may have rather narrow obovate leaves. TAXONOMIC AFFINITIES: Morphologically, this species is very different from other western Mediterranean species, mainly because of the presence of basal leaf rosettes. It was probably this particular appearence that led Cardona and Contandriopoulos (1979) to hypothesize H. crassifolium to be a paleoendemic. In contrast, our phylogenetic study based on nuclear rDNA ITS sequence data revealed it to be closely related to species of H. sect. Stoechadina, which are clearly derived within the genus, grouped in an unresolved monophyletic clade. NOMENCLATURAL NOTES: This species has often been wrongly called H. ambiguum (Clapham 1976; Bonafè 1980; Bolòs and Vigo 1996) or H. lamarckii (Porta 1887; Knoche 1922). For detailed explanations see Galbany-Casals et al. (2006). Hybrids H. crassifolium  H. stoechas Gnaphalium ambiguum Pers., Syn. Pl. 2: 417 (1807). : Helichrysum ambiguum (Pers.) C. Presl, Fl. Sicul. 1: 29 (1826). Can. J. Bot. Vol. 84, 2006 : H. lamarckii Cambess. in Mém. Mus. Hist. Nat. 14: 269, t. 7 (1827). REMARKS: Intermediate individuals between H. crassifolium and H. stoechas, particularly with regards to capitula shape and leaf shape and size, can be observed at two localities, one each in Majorca and Minorca. At both localities, some individuals appear to be pure H. crassifolium, others seem strictly H. stoechas. Among these, we collected several intermediate individuals which present all gradations between these two potential parental species. Cosı́n et al. (2004) reported that several hybridization and introgression events between these two species have occurred at these and other localities, following their study based on cpDNA trnL-trnF spacer and nrDNA ETS sequences. For nomenclatural remarks see Galbany-Casals et al. (2006). H. crassifolium  H. rupestre In the same Majorcan locality we also discovered some intermediate individuals between H. crassifolium and H. rupestre. These also present an intermediate morphological appearence with regards to leaf and capitula shape and size between the two potential parental species. REMARKS: 2. Helichrysum stoechas (L.) Moench, Methodus: 575 (1794) : Gnaphalium stoechas L., Sp. Pl.: 853 (1753). LECTOTYPE: (Galbany-Casals et al. 2006, p. 492) [Southern France], Iles de Hyères, ‘‘In insulis stoechadibus’’ (UPS, Herb. Burser XV(1): 22!). = H. decumbens Cambess. in Mém. Mus. Hist. Nat. 14: 27 (1827). = H. caespitosum (C. Presl) DC., Prodr. 6: 182 (1838), nom. illeg., non H. caespitosum (Lam.) DC., Prodr. 6: 173 (1838). : H. siculum (Spreng.) Boiss., Fl. Orient. 3: 229 (1875), nom. illeg., non H. siculum Jord. & Fourr., Brev. Pl. Nov. 2: 67 (1868). = H. conglobatum Steud., Nomencl. Bot., ed. 2, 2: 738 (1840). = H. stoechas subsp. barrelieri (Ten.) Nyman, Consp. Fl. Eur. 1: 381 (1879). : H. barrelieri (Ten.) Greuter in Greuter & Rech. f. in Boissiera 13: 138 (1967). = H. scandens Guss., Fl. Sicul. Syn. 2: 465 (1844). – H. decumbens var. spathulata Raulin, Description Physique de l’Ile de Crète: 480 (1869), nom. inval. ILLUSTRATION: Pignatti (1982, pp. 42, 43 [sub. H. siculum]); Alavi (1983, p. 64); Devesa (1987, p. 35). DESCRIPTION: Sub-shrubby to shrubby perennials, arachnoid to densely tomentose, generally aromatic, sometimes not, up to 50(70) cm high. Vegetative stems several, erect, ascendent or decument, leafy all their length; flowering stems several, erect, ascendent or decumbent, leafy all their length, more densely so basally. Lower and medial cauline leaves of the flowering and vegetative stems 4–30(45) mm  0.4–3(7) mm, linear, narrowly lanceolate or narrowly oblanceolate, sometimes spathulate, subdecurrent, obtuse, concolorous or discolorous, subglabrous to densely tomentose and eglandular on the adaxial surface, densely tomentose and eglandular to densely glandular on the abaxial surface, margin generally # 2006 NRC Canada Galbany-Casals et al. 1215 Fig. 4. Phyllary series in Helichrysum sect. Stoechadina, left to right, outermost to innermost. (A) H. crassifolium [Rodrı́guez s.n. (BC 614789)]. (B) H. stoechas [Blanco & M. Galbany s.n. (BCN 25245)]. (C) H. rupestre [Sáez s.n. (BCN 20719)]. (D) H. errerae [Italy, insula Pantellaria, 1855, E. & A. Huet du Pavillon s.n. (G)]. (E) H. angustifolium [Pellanda s.n. (MA 125197)]. (F) H. heldreichii [Rechinger fil. 13792 (W 12974)]. (G) H. italicum subsp. microphyllum [Italy, Sardinia, arrondissement de Tempio, 2-VII-1882, Reverchon s.n. (Plantes de Sardaigne 96) (G)]. (H) H. italicum subsp. italicum [Lacaita s.n. (Flora Italica exsiccata ser. III No. 2376) (WU)]. (I) H. italicum subsp. siculum [M. Galbany s.n. (BCN 24030)]. (J) H. serotinum subsp. picardii [Garcı́a Martı́nez s.n. (SANT 12448)]. (K) H. serotinum subsp. serotinum [M. Galbany s.n. (BCN 25233)]. Scale bar = 1 mm. # 2006 NRC Canada 1216 Can. J. Bot. Vol. 84, 2006 Fig. 5. Map of Balearic Islands showing distribution of Helichrysum crassifolium (H. crass) and intermediate specimens (interm spec) of H. crassifolium and Helichrysum rupestre (H. rup) and H. crassifolium and Helichrysum stoechas (H. stoe). revolute, sometimes flat, not undulate. Lower and medial cauline leaves of the flowering stems patent to erecto-patent, decreasing in size to the synflorescence; uppermost leaves appressed to the stem and more laxly arranged. Synflorescences corymbose, terminal, dense to rather lax, 6–44 mm  12–64 mm, with 3–72 capitula. Capitula 4–6.5(8) mm  4–6.5(8) mm, broadly campanulate to hemispherical (Fig. 2B), heterogamous, with 21–75 yellow florets; pistillate florets 4–24, hermaphroditic florets 15–54. Phyllaries 22–53, laxly imbricate, papery; outermost phyllaries 2– 4.5(5.5) mm  1–3 mm, totally papery, elliptic, ovate or obovate, acute or obtuse, subglabrous and eglandular at the base; middle phyllaries 3–5.5 mm  1.8–3.8 mm, ovate, elliptic, obovate or spathulate, acute or obtuse, stereome subglabrous to arachnoid and eglandular to densely glandular; innermost phyllaries 3.2–6 mm  0.6–1.8 mm, linear, narrowly lanceolate, narrowly oblanceolate or narrowly spathulate, acute or obtuse, stereome subglabrous to arachnoid-tomentose and eglandular to densely glandular; mean length of innermost phyllaries / mean length of outermost phyllaries 0.97–1.95; mean length of innermost phyllaries / mean length of middle phyllaries 0.93–1.18. (Fig. 4B). Receptacle naked, flat or concave, smooth or alveolate. Corolla of the pistillate florets 2.4–4.6 mm; corolla of the hermaphroditic florets 2.9–5.1 mm. Middle phyllaries length / mean length of the hermaphroditic florets 0.92–1.34. Cypselae 0.6–1.1 mm  0.2–0.6 mm, cylindrical to ovoid-cylindrical, with regularly scattered white, rarely golden, duplex hairs, sometimes glabrous. Pappus bristles 2.6–4.9 mm long; apical cells obtuse. CHROMOSOME NUMBER: 2n = 28 (Lorenzo-Andreu and Garcı́a Sanz 1950; Gadella et al. 1966; D’Amato 1971; Fernandes and Queirós 1971; Queirós 1973; Natarajan 1977; Brullo et al. 1978; Loon and Jong 1978; Natarajan 1978; Love and Love 1982; Amore et al. 1999); 2n = 28 + 4B (Namur and Verlaque 1976). DISTRIBUTION: Widespread throughout the entire Mediterranean area (Fig. 6). HABITAT: Helichrysum stoechas grows in a variety of open habitats, including shrubby and herbaceous formations, road banks and path margins, abandoned fields, maritime rocks, cliffs, and sand dunes; on several substrate types, such as granitic, schistose, gypseous or limestone rocky soils. It is a very common species throughout nearly the entire geographical area. It is often one of the first pioneer species to colonize newly opened areas. Altitudinal range: 0–1800 m. PHENOLOGY: Flowers (January) March–July (December). It is the most variable and widely distributed species of the section. This variability extends to its habit, the size of the synflorescence, the size and shape of leaves, the density of leaf indumentum, the size of the capitula, and the density of glandular hairs on leaves and phyllaries. Specimens that grow near the sea, both in rocky and sandy soils, are usually dwarf, ascendent or decumbent, VARIABILITY: # 2006 NRC Canada Galbany-Casals et al. densely tomentose, and not very glandular plants, with short leaves and small synflorescences with a small number of capitula. Several taxa have been described with the aim of recognising these maritime phenotypes throughout the Mediterranean area: H. decumbens and H. stoechas var. caespitosum Willk. from the Mediterranean coast of Spain; H. stoechas var. argentatum P. Palau from the Balearic Islands (Cabrera); H. stoechas var. maritimum Lange from the Atlantic coast of Spain; H. caespitosum var. compactum Guss. from Sicily and H. stoechas var. psammiticum Fiori from the Toscane coast of Italy. In the field we have observed that specimens growing in sand dunes, but protected from the wind by taller vegetation are erect and taller than nearby specimens exposed to the wind. Other specimens of H. stoechas growing in coastal localities have a very different appeareance, while remaining dwarf and densely tomentose, due to their broad spathulate leaves with flat margins. Several taxa have been described, as well, to recognise these broad-leaf maritime phenotypes: H. conglobatum from the coast of Libya; H. siculum var. brachyphyllum Boiss. from several eastern Mediterranean coastal localities and H. rupestre var. latifolium Caball. from the Atlantic coast of Morocco. These broad-leaf tomentose specimens can be observed in coastal localities from Morocco, Algeria, Tunisia, Libya, Egypt, Crete, and Cyprus, as well as in Majorca, albeit rarely, whereas other specimens growing in the same countries but inland are erect, taller, and have narrow, linear, often revolute leaves, with the adaxial surface subglabrous to tomentose. Occasionally, plants growing in coastal localities may have cypselae without duplex hairs, although this feature is not correlated with any other morphological character. Several phenotypes are also observed in inland populations of H. stoechas. In the western Mediterranean area, mainly Portugal, Spain, Morocco, Algeria, Tunisia, France, and Italy, they are generally tomentose and glandular, with leaves always with revolute margins. In the eastern Mediterranean area, mainly Greece, Cyprus, Turkey, and Libya, they are not so glandular, the adaxial surface of leaves subglabrous to arachnoid-tomentose and they usually have some leaves with flat margins. However, we have studied numerous eastern specimens with all leaves narrowly linear with revolute margins, and some western specimens with lanceolate or oblanceolate leaves with flat margins. Clapham (1976) provisionally recognised two subspecies, H. stoechas subsp. stoechas from the western Mediterranean area and H. stoechas subsp. barrelieri from the eastern Mediterranean area, based on leaf length differences and on innermost phyllaries / outermost phyllaries differences. With regards to these characters there is no significant difference between western and eastern specimens (see Statistical Analysis section and Table 3). Moreover, outermost phyllaries are acute or obtuse both in eastern and western specimens and this character similarly does not correlate with the distribution as Clapham (1976) stated. Following our own field observations and after the study of numerous herbarium specimens, we conclude that all such variability is mainly determined by environmental conditions. On the contrary, reproductive characters such as capitula shape and structure are conserved and do not vary among the described phenotypes. Moreover, none of the extant phenotypes can be correlated with a defined and isolated geographic area. In 1217 conclusion, we believe that no infraspecific taxon can be recognized under H. stoechas’s variability. Finally, some Libyan specimens with creamy instead of yellow phyllaries can be observed [Tripolitania, steppa di Tagiura, 22-III-1931, Zodda s.n. (FI); Aı̈n Zara, 19-II-1913, Pampanini s. n. (FI)]. TAXONOMIC AFFINITIES: Helichrysum stoechas is closely related to H. rupestre. The two species are sometimes difficult to distinguish, especially in North Africa where their characteristics partly overlap, and where intermediate specimens are found. Similarities and differences between the species, as well as intermediate specimens, are described under H. rupestre. 3. Helichrysum rupestre DC., Prodr. 6: 182 (1838) : Gnaphalium rupestre Raf., Précis Découv. Somiol.: 41 (1814), nom. illeg., non. Pourr. in Hist. & Mém. Acad. Roy. Sci. Toulouse 3: 320 (1788). : H. stoechas subsp. rupestre (Raf.) Maire in Jahand. & Maire, Cat. Pl. Maroc 3: 751 (1934). (Galbany-Casals et al. 2006, p. 492) Palermo, in rupibus calcareis, V, Todaro 551 (PAL 8720!; isoneotypes: FI!, K!, P!, PH 1029697 photo!). NEOTYPE: = H. pendulum (C. Presl) C. Presl, Fl. Sicul. 1: 29 (1826). = H. fontanesii Cambess. in Mém. Mus. Hist. Nat. 14: 270 (1827). = H. saxatile Moris, Fl. Sardoa 2: 387, t. 82 (1840–1843). = H. nebrodense Heldr. in Ann. Accad. Aspir. Naturalisti 1: 286 (1843). = H. panormitanum Tineo ex Guss., Fl. Sicul. Syn. 2: 467 (1844). = H. stramineum Guss., Fl. Sicul. Syn. 2: 467 (1844). = H. boissieri Nyman, Consp. Fl. Eur. 1: 381 (1879). = H. rupestre var. melitense Pignatti in Giorn. Bot. Ital. 113 (5–6): 363 (1980). : H. melitense (Pignatti) Brullo, Lanfranco, Pavone & Ronsisvalle in Giorn. Bot. Ital. 122, suppl. 1: 9. (1988). = H. rupestre var. messerii Pignatti in Giorn. Bot. Ital., 113 (5–6): 363 (1980). = H. hyblaeum Brullo in Colloq. Phytosociol. 21: 630 (1995). ILLUSTRATION: Cambessèdes (1827: t. 8, pl. 17 [sub. H. fontanesii]); Arrigoni et al. (1980, p. 246 [sub. H. saxatile]); Pignatti (1982, p. 42 [sub. H. saxatile], p. 43); Devesa (1987, p. 35). DESCRIPTION: Shrubby perennials, arachnoid to densely tomentose, not aromatic, 50–150 cm high. Vegetative stems several, erect, leafy all their length; flowering stems several, erect or ascendent, leafy all their length, more densely so basally. Lower and medial cauline leaves of the flowering and vegetative stems (13)30–95 mm  (1)2–8.5 mm, linear, lanceolate, oblanceolate or narrowly spathulate, subdecurrent, obtuse, concolorous or discolorous, subglabrous to tomentose and eglandular on the adaxial surface, arachnoid to densely tomentose and eglandular to sparsely glandular on the abaxial surface, margin revolute or flat, not undulate. Lower cauline leaves of the flowering stems reflexed, medial leaves patent to erecto-patent, decreasing in size to the # 2006 NRC Canada 1218 Can. J. Bot. Vol. 84, 2006 Fig. 6. Distribution of Helichrysum stoechas. synflorescence; uppermost leaves appressed to the stem and laxly arranged. Synflorescences corymbose, terminal, dense to rather lax and branched, 13–95 mm  22–125 mm, with 7–152 capitula. Capitula (4)5–8 mm  (4)5–8 mm, broadly campanulate to hemispherical (Fig. 2C), heterogamous, with 20–88 yellow florets; pistillate florets 5–29, hermaphroditic florets (13)22–62. Phyllaries 26–54, laxly imbricate, papery; outermost phyllaries (1.9)2.5–5 mm  (1.3)1.6–3.2 mm, totally papery, ovate or elliptic, acute or obtuse, glabrous and eglandular at the base; middle phyllaries 3–6  2–3.8 mm, obovate to spathulate, acute or obtuse, stereome arachnoid and eglandular to sparsely glandular; innermost phyllaries 3.4–6.1 mm  0.5–1.6 mm, linear, narrowly lanceolate, narrowly oblanceolate or narrowly spathulate, acute or obtuse, stereome subglabrous to arachnoid-tomentose and eglandular to sparsely glandular; mean length of innermost phyllaries / mean length of outermost phyllaries 1.01–2.09; mean length of innermost phyllaries / mean length of middle phyllaries 0.96–1.21. (Fig. 4C). Receptacle naked, flat or concave, smooth or alveolate. Corolla of the pistillate florets 2.7– 5 mm; corolla of the hermaphroditic florets 3.1–5.4 mm. Middle phyllaries length / mean length of the hermaphroditic florets 0.91–1.27. Cypselae 0.7–1.1  0.3–0.8 mm, cylindrical to ovoid-cylindrical, with regularly scattered white duplex hairs. Pappus bristles 2.5–4.9 mm long; apical cells obtuse. CHROMOSOME NUMBER: 2n = 28 (D’Amato 1971; Cardona 1976; Brullo et al. 1979). Distributed in the west-central Mediterranean area: south Spain and Balearic Islands (Majorca and Ibiza), Morocco, Algeria, and Sardinia, Sicily, and Malta (Fig. 7). DISTRIBUTION: HABITAT: Chasmophytic on limestone rock crevices and maritime cliffs, rarely on sandy soil. Altitudinal range: 0– 1850 m. PHENOLOGY: Flowers (January) February–July. VARIABILITY: Helichrysum rupestre is a variable species, probably because of its disjunct distribution. In Majorca (Ba- learic Islands), H. rupestre specimens, which were described by Cambessèdes (1827) under the name H. fontanesii, usually have subglabrous to arachnoid leaves on the adaxial surface, often with revolute margins, although leaves with flat margins can also be observed. In North Africa (Algeria and Morocco) H. rupestre specimens are very similar to those of Majorca. In Ibiza (Balearic Islands) some specimens may have very wide leaves, with flat margins, and were distinguished by Font Quer (1920) at the varietal level (H. fontanesii var. latifolium) from those of Majorca. In Gibraltar (south Spain), Sardinia, Sicily, and Malta, plants of H. rupestre usually have arachnoid–tomentose to tomentose leaves on the adaxial surface, with both revolute and flat margins. Particularly on Gozo island, plants may have very wide leaves, and also were described by Pignatti (1980) as a different taxon (H. rupestre var. melitense). Although all the above-mentioned trends can be observed readily, after studying numerous specimens from the entire range, as well as the types of all these taxa, we conclude that those vegetative characters concerning leaf margin and leaf indumentum density are widely variable, as is typical of many other Helichrysum species, and are not strictly correlated with a limited geographic area. We consider all of them to be synonyms of H. rupestre. Several taxa at different taxonomic ranks were also described from Sicily and adjacent islands, H. nebrodense, H. panormitanum, H. pendulum, and H. stramineum, among others. Whenever possible, we examined the type materials, and numerous specimens from the areas where these taxa are located. We have been unable to find any morphological character that would permit taxonomic recognition of any of them, as all character variation fits within the range of H. rupestre’s morphological variability. Clapham (1976), Pignatti (1982), and Baccheta et al. (2003) recognise H. saxatile Moris, endemic to Sardinia, as a species distinct from H. rupestre, based on differences in capitula shape and size, the capitula of H. saxatile being smaller and narrower than those of H. rupestre. After studying numerous specimens from Sardinia, both in the field and # 2006 NRC Canada Galbany-Casals et al. from herbaria, we conclude that those plants which have been called H. saxatile comprise, on the one hand, certain specimens which have rather large, broadly campanulate to hemispherical capitula, which certainly fit within H. rupestre, and, on the other hand, some that have smaller and narrowly campanulate capitula, as well as shorter leaves in general. In our opinion, the latter specimens possess intermediate characters between H. rupestre and H. italicum subsp. microphyllum and may stem from hybridization and introgression events (see further remarks in the Hybrids section under H. italicum). In fact, Moris’ collections from Sardinia labelled H. saxatile are heterogeneous and contain both specimens of H. rupestre and the above-mentioned hybrids. Arrigoni et al. (1980) designated one specimen from SASSA, which corresponds to H. rupestre, as lectotype of this taxon. TAXONOMIC AFFINITIES: Helichrysum rupestre is closely related to the widespread Mediterranean H. stoechas. In fact, they do not differ in any qualitative character, both having a similar habit, broadly campanulate to hemispherical capitula with papery, laxly imbricate phyllaries. For this reason, Maire (1934) combined H. rupestre at the subspecific level under H. stoechas. However, they can usually be separated since H. rupestre specimens are usually more robust and less glandular, with longer and wider leaves and with larger capitula than those of H. stoechas (see also Table 2), although these quantitative characters sometimes overlap. In particular, distinguishing the two species is difficult in certain North African localities, where the two species are sympatric or nearly sympatric and some intermediate specimens can be observed (see hybrids). However, the habitat preferences of the two species are different: H. stoechas grows in any type of soil and is found in open shrubby formations, road banks, abandoned cultivated fields and in rocky or sandy littoral habitats. In contrast, H. rupestre favors limestone rocks crevices and maritime cliffs, rarely growing on sandy soil. With regards to vegetative morphology, H. rupestre resembles H. angustifolium, H. errerae, and H. heldreichii, in the robustness of its habit, as well as in its long leaves and the large synflorescences. For differences between H. rupestre and these other species see the Taxonomic affinities section under each of these species. Hybrids H. rupestre  H. stoechas H. valentinum Rouy in Bull. Soc. Bot. France 35: 117 (1888). REMARKS: Some plants from the eastern Iberian Peninsula (Alicante province) were described by Rouy (1888) as H. valentinum Rouy and cited as H. rupestre by Bolòs and Vigo (1996). After visiting this area and studying numerous herbarium specimens, we found that these plants, which are intermediate in morphology between H. rupestre and H. stoechas, can be observed at several localities throughout this area. In our opinion, these plants constitute a poorly defined taxon, as specimens possessing a gradation of morphological characters exist between H. stoechas, which is also present nearby, and H. rupestre. Indeed, from our field observations and germination trials, hybrids appear fertile, pro- 1219 ducing cypselae that germinate and produce fertile adult plants, thereby allowing introgression to occur. The specimens that are closest in morphology to H. rupestre often grow on maritime vertical limestone cliffs, while those more similar to H. stoechas grow on rocky soil among shrubby vegetation or on road and field banks. We believe all these specimens may have originated from ancient hybridization and introgression events between H. rupestre and H. stoechas, as the former is not found in this area at present. Other intermediate specimens between H. rupestre and H. stoechas, presumably hybrids, are also found in several localities in Algeria, southern Spain, Balearic Islands (Majorca and Ibiza), and Sicily. Both potential parental species are sympatric or nearly sympatric in these localities. 4. Helichrysum errerae Tineo, Pl. Rar. Sicil. 2: 27 (1846) : H. saxatile subsp. errerae (Tineo) Nyman, Consp. Fl. Eur.: 381 (1879). : H. saxatile var. errerae (Tineo) Fiori in Fiori & Paol., Fl. Italia 3: 282 (1904). : H. rupestre var. errerae (Tineo) Pignatti in Giorn. Bot. Ital. 113 (5–6): 363 (1980). (Galbany-Casals et al. 2006, p. 492) Pantelleria, IV1863, Errera s.n. (FI!). DESCRIPTION: Shrubby or sub-shrubby perennials, arachnoid to tomentose, not aromatic, up to 50 cm high. Vegetative stems several, erect, leafy all their length; flowering stems several, erect, leafy all their length, more densely so basally. Lower and medial cauline leaves of the flowering and vegetative stems 23–58  1.5–8, oblanceolate to narrowly spathulate, subdecurrent, obtuse, discolorous, subglabrous to arachnoid and eglandular on the adaxial surface, tomentose and sparsely glandular on the abaxial surface, margin flat, rarely revolute, not undulate. Lower cauline leaves of the flowering stems reflexed, medial leaves patent to erecto-patent, decreasing in size to the synflorescence; uppermost leaves appressed to the stem and laxly arranged. Synflorescences corymbose, terminal, lax and branched, 23–75 mm  36– 90 mm, with 24–103 capitula. Capitula 4.5–6 mm  4– 7 mm, broadly campanulate (Fig. 2D), heterogamous, with 24–40 yellow florets; pistillate florets 7–13, hermaphroditic florets 15–29. Phyllaries 28–40, laxly imbricate, papery, except the outermost coriaceous, or at least in their proximal half; outermost phyllaries 2.5–3.9 mm  0.9–2 mm mm, totally coriaceous, rarely with the distal half papery, narrowly oblanceolate to narrowly spathulate, obtuse, completely tomentose and eglandular; middle phyllaries 3–4 mm  1.9– 2.8 mm, spathulate, obtuse, stereome arachnoid and eglandular; innermost phyllaries 3.9–4.5 mm  0.6–1.3 mm, oblanceolate to narrowly spathulate, obtuse, stereome arachnoid to tomentose and eglandular to sparsely glandular; mean length of innermost phyllaries / mean length of outermost phyllaries 1.21–1.45; mean length of innermost phyllaries / mean length of middle phyllaries 1.03–1.16. (Fig. 4D). Receptacle flat, smooth or alveolate. Corolla of the pistillate florets 2.4–3.2 mm; corolla of the hermaphroditic florets 2.9–4 mm. Middle phyllaries length / mean length of the hermaphroditic florets 1.06–1.11. Cypselae 0.8– 1.1 mm  0.4–0.6 mm, cylindrical to ovoid-cylindrical, NEOTYPE: # 2006 NRC Canada 1220 Can. J. Bot. Vol. 84, 2006 Fig. 7. Distribution of Helichrysum angustifolium (H. ang), Helichrysum errerae (H. err), Helichrysum heldreichii (H. held), Helichrysum rupestre (H. rup), and intermediate specimens (interm spec) of H. angustifolium and Helichrysum italicum subsp. italicum (H. ita subsp. ita), Helichrysum rupestre and H. italicum subsp. microphyllum (H. ita subsp. micro), and H. rupestre and H. stoechas (H. stoe). with regularly scattered white duplex hairs. Pappus bristles 2.8–3.8 mm long; apical cells obtuse. CHROMOSOME NUMBER: 2n = 28 (D’Amato 1971). DISTRIBUTION: Endemic to Pantelleria Island (southwestern Sicily) (Fig. 7). HABITAT: Maritime volcanic rocks and cliffs. PHENOLOGY: Flowers April–May. TAXONOMIC AFFINITIES: Several authors combined this species at different subspecific ranks under H. rupestre [sub. H. saxatile Moris] from Sardinia because of the similarities in vegetative characters and capitula shape between the two species; H. rupestre is the species most closely related to H. errerae. However, both species can be clearly distinguished as H. errerae has oblanceolate to spathulate leaves, and the outermost phyllaries are partly to completely coriaceous and tomentose (Fig. 4C), whereas H. rupestre has linear, lanceolate or narrowly oblanceolate leaves, and the outermost phyllaries are completely papery and glabrous (Fig. 4D). 5. Helichrysum heldreichii Boiss., Fl. Orient. 3: 229 (1875). HOLOTYPE: In rupibus Gorque de Hagio Rumeli, 8-VII-1846, Heldreich s.n. (G-BOIS!; isotypes: BC 31004!, BM 45958!, G!, W!). ILLUSTRATION: Fig. 8A. Shrubby perennials, tomentose, slightly aromatic, up to 70 cm high. Vegetative stems several, erect, leafy all their length; flowering stems several, erect, leafy all their length, more densely so basally. Lower and medial cauline leaves of the flowering and vegetative stems 29–60 mm  1–5 mm, linear, lanceolate, or oblanceolate, subdecurrent, obtuse, discolorous, arachnoid, and eglandular on the adaxial surface, densely tomentose and sparsely glandular on the abaxial surface, margin revolute, rarely flat, not undulate. Lower cauline leaves of the flowering stems reflexed, medial leaves patent to erecto-patent, decreasing in size to the synflorescence; uppermost leaves appressed to the stem and laxly arranged. Synflorescences corymbose, terminal, lax and branched, 17–42 mm  28–52 mm, with 30–211 capitula. Capitula 4–5 mm  2–3 mm, narrowly campanulate (Fig. 2F), heterogamous, with 17–37 yellow florets; pistillate florets 6–9, hermaphroditic florets 10–28. Phyllaries 20–37, laxly imbricate, papery except the outermost coriaceous; outermost phyllaries 1.3–3 mm  0.3–1.2 mm mm, the proximal half coriaceous, the distal half papery, linear, narrowly lanceolate or narrowly oblanceolate, acute, tomentose and DESCRIPTION: # 2006 NRC Canada Galbany-Casals et al. eglandular in the proximal half, glabrous in the distal half; middle phyllaries 3.5–4 mm  1.2–1.5 mm, oblanceolate or elliptic, acute or obtuse, stereome arachnoid and sparsely glandular; innermost phyllaries 3.8–4.5 mm  0.5–1 mm, linear, narrowly lanceolate, narrowly oblanceolate, or narrowly spathulate, acute, rarely obtuse, stereome arachnoid, and sparsely glandular; mean length of innermost phyllaries / mean length of outermost phyllaries 1.88–1.89; mean length of innermost phyllaries / mean length of middle phyllaries 0.99–1.13. (Fig. 4F). Receptacle flat or convex, alveolate. Corolla of the pistillate florets 2.2–3.2 mm; corolla of the hermaphroditic florets 3–3.8 mm. Middle phyllaries length / mean length of the hermaphroditic florets 1.11–1.33. Cypselae 0.8–1 mm  0.3–0.4 mm, ovoid-cylindrical, with regularly scattered white duplex hairs. Pappus bristles 2.5–3 mm long; apical cells acute. CHROMOSOME NUMBER: 2n = 28 (de Montmollin 1986). DISTRIBUTION: . Endemic to a very restricted area of southwestern Crete. (Fig. 7). HABITAT: Chasmophytic, in limestone rock crevices on vertical cliffs. Altitudinal range: 200–1000 m. PHENOLOGY: Flowers May–August. TAXONOMIC AFFINITIES: Helichrysum heldreichii resembles H. rupestre and H. angustifolium in its robustness and leaf length, although it seems more closely related to the latter because of the similarity in capitula shape, campanulate with the outermost phyllaries at least partly coriaceous and tomentose in both species. However, H. heldreichii has smaller capitula, laxly arranged phyllaries, and the outermost phyllaries coriaceous and tomentose only in the proximal half, whereas H. angustifolium has larger capitula, densely arranged phyllaries, and the outermost generally completely coriaceous and tomentose, although they can sometimes be coriaceous and tomentose only in the proximal half. 6. Helichrysum angustifolium (Lam.) DC. in Lam., Fl. Franç. ed. 3, 6: 467 (1815) : Gnaphalium angustifolium Lam., Encycl. 2: 746 (1788). : H. litoreum Guss., Fl. Sicul. Syn. 2: 468 (1844), nom. illeg. LECTOTYPE: (Hilliard and Burtt 1981b, p. 238) ex agro Neap. Chev., herb. Jussieu n8 8536 (P!). = Helichrysum italicum var. ginzbergeri Ronniger in Feddes Repert. 24: 201 (1927). LECTOTYPE: (Galbany-Casals et al. 2006, p. 492) Dalmatien, Ragusa, auf du Pettini, 6-VI-1926, E. Korb s.n. (W!). ILLUSTRATION: Fig. 8C. DESCRIPTION: Shrubby perennials, arachnoid to arachnoid– tomentose, not aromatic, up to 80 cm high. Vegetative stems several, erect, leafy all their length; flowering stems several, erect or ascendent, leafy all their length, more densely so basally. Lower and medial cauline leaves of the flowering and vegetative stems (19)28– 80 mm  0.6–2 mm, linear, subdecurrent, obtuse, discolorous, subglabrous to arachnoid-tomentose and 1221 eglandular on the adaxial surface, densely tomentose and eglandular to sparsely glandular on the abaxial surface, margin revolute, rarely flat, not undulate. Lower and medial cauline leaves of the flowering stems patent to erecto-patent, decreasing in size to the synflorescence; uppermost leaves appressed to the stem and laxly arranged. Synflorescences corymbose, terminal, generally lax and branched, rarely dense, 17– 110 mm  28–90 mm, with 34–306 capitula. Capitula 4–6 mm  2.5–4.5 mm, cylindrical to narrowly campanulate (Fig. 2E), heterogamous, with 15–31 yellow florets; pistillate florets 4–10, hermaphroditic florets 10–26. Phyllaries 24–36, densely imbricate, papery except the outermost coriaceous; outermost phyllaries 1.3–2 mm  0.6– 1.8 mm mm, totally coriaceous (rarely with the distal half papery), ovate to oblong–ovate, acute or obtuse, completely tomentose and eglandular; middle phyllaries 3–4.6 mm  1.9–2.8 mm, obovate to spathulate, acute or obtuse, stereome arachnoid and sparsely glandular; innermost phyllaries 3–5 mm  0.5–1.1 mm, linear, acute or obtuse, stereome arachnoid to arachnoid–tomentose and sparsely to densely glandular; mean length of innermost phyllaries / mean length of outermost phyllaries 2.01–2.80; mean length of innermost phyllaries / mean length of middle phyllaries 1.02–1.1 (Fig. 4E). Receptacle flat or concave, alveolate. Corolla of the pistillate florets 2.5– 3.8 mm; corolla of the hermaphroditic florets 3–4.4 mm. Middle phyllaries length / mean length of the hermaphroditic florets 1–1.18. Cypselae 0.9–1.1 mm  0.4–0.7 mm, ovoid-cylindrical, with regularly scattered white duplex hairs. Pappus bristles 2.8–3.9 mm long; apical cells obtuse. CHROMOSOME NUMBER: 2n = 28 (Tornadore et al. 1974). DISTRIBUTION: West-central Italy, to some islands in the Tyrrhenian sea (Capri, Ischia, the Archipelago Ponziane, the Archipelago Lipari, and the Archipelago Toscano) and to the Croatian Istra Peninsula (Fig. 7). HABITAT: Limestone and volcanic maritime rocks, in shrubby vegetation and on littoral sand dunes. Altitudinal range: 0– 900 m. PHENOLOGY: Flowers (April) May–August. VARIABILITY: Helichrysum angustifolium is not, in general, a very variable species, although some specimens growing very close to the sea are noticeably shorter, have a denser habit and much shorter leaves [Sabaudia, dune littoranee di Torre Paola, 21-IV-1965, Bavazzano & Ricceri s.n. (FI); Isolotto di Porto Ercole (Grosseto), 0–40 m, suolo calcareo, 27V-1988, Baldini s.n. (FI); Isola di Giannutri, da Cala Maestra alla Domus, 8-V-1959, Gori & Gramuglio s.n. (FI); Isola di Pianosa, strada tra il Paese e Villa Romana, 21-V-1971, Francini Corti s.n. (FI); Isola di Pianosa, Punta Marchese, 12-VI-1973, Sabato s.n. (FI)]. This short and dense habit probably reflects an adaptation to maritime ecological conditions, as occurs in other Mediterranean Helichrysum species such as H. stoechas. TAXONOMIC AFFINITIES: On the one hand, with regards to reproductive characters, H. angustifolium is closely related to H. italicum and H. serotinum, as these three species have cylindrical to narrowly campanulate capitula, with the phyllaries densely imbricate, and outermost phyllaries coriaceous and tomentose at least in the proximal half. Helichrysum se# 2006 NRC Canada 1222 Can. J. Bot. Vol. 84, 2006 Fig. 8. Whole plant drawings, as pressed. (A) Helichrysum heldreichii [Garnatje 134 & Luque (BCN 6123)]. (B) Helichrysum italicum subsp. siculum [M. Galbany s.n. (BCN 24030)]. (C) Helichrysum angustifolium [Lluent et al. s.n. (BCN 20725)]. Scale bar = 2 cm. # 2006 NRC Canada Galbany-Casals et al. rotinum differs from the other two species in its naked cypselae, which never bear duplex hairs. Helichrysum angustifolium and H. italicum basically differ in their habit and in the density of glandular hairs. Helichrysum angustifolium is in general a very robust plant, with longer leaves and many more capitula, and usually less glandular than H. italicum on the abaxial side of leaves and on the phyllaries. Both species grow together in certain areas, as shown by herbarium sheets including elements of both species [M. Vesuvio, 200–300 m, 20-VI-1912, Pellanda s.n. (BC 30997)], and a few intermediate specimens observed at several localities, which could have originated by hybridization (see below under Hybrids). On the other hand, with regards to vegetative characters, H. angustifolium in particular resembles H. rupestre by its robustness, long leaves, and large synflorescences. As natural hybridization is rather common among Helichrysum species, the potential hybrid origin of H. angustifolium from past hybridization events between H. italicum and H. rupestre cannot be ruled out, as H. angustifolium seems to share morphological characters of the two potential parents. In fact, there is an unusual herbarium specimen from Croatia [Ragusa, V-1890, Heider s. n. (WU)] with the typical H. angustifolium robust habit but with broader capitula with papery phyllaries, thus with capitula more similar to those of H. rupestre than to those of H. angustifolium. This specimen could prove past hybridization between the two species, as H. rupestre is not found in this area at present. It can be hypothesized that H. rupestre possibly occupied a larger distribution area in the past. NOMENCLATURAL REMARKS: Helichrysum angustifolium was described by Lamarck (1788) as Gnaphalium angustifolium. Lamarck wrongly indicated this species to be from Spain and Naples. He probably included in his concept of G. angustifolium the Iberian plants later described as Helichrysum serotinum (DC.) Boiss., believing that they both corresponded to a single species. The original Jussieu’s specimen used by Lamarck for his description of G. angustifolium only contains one element, which is a robust plant, with long linear leaves, 48–57 mm  1.3–2 mm, and with a large and branched inflorescence, 140 mm broad, with numerous capitula. The capitula are narrowly campanulate and the phyllaries densely imbricate, the outermost coriaceous and tomentose. This specimen certainly corresponds to the west-central Italian endemic species. de Candolle (1815) transferred Gnaphalium angustifolium to the genus Helichrysum, and wrongly reported that this species occurred in Corsica, southern France and northern Italy. He probably also included H. italicum in his concept of H. angustifolium, or perhaps he was directly referring to H. italicum, misapplying the name G. angustifolium Lam., due to the geographic area indicated, and because H. italicum was reported as a doubtful synonym. Gussone (1844) thought that G. angustifolium and H. angustifolium sensu DC. were actually different species and combined the former under the genus Helichrysum with the name H. litoreum Guss., which became a superfluous illegitimate name, although this is the name used in some recent floristic treatments (Clapham 1976; Pignatti 1982). Ronniger (1927) described Helichrysum italicum var. ginzbergeri based on material from Croatia and stated in the 1223 diagnosis that these plants have leaves 40–50  2–3 mm, narrowly spathulate, the young ones with flat margins, and cylindrical capitula, 4–4.5 mm  2.5–3 mm. Although he placed this new variety under H. italicum, a species that is present in this area, after studying the type specimen we believe that it better corresponds to H. angustifolium, as they are much more robust than the specimens of H. italicum subsp. italicum that grow in close proximity. Hybrids H. angustifolium  H. italicum Gnaphalium glutinosum Ten., Syll. Pl. Fl. Neapol.: 424 (1831). H. italicum var. pseudolitoreum Fiori in Fiori & Paol., Fl. Italia 3: 283 (1904). H. italicum f. intermedium Pamp., Piante San Marino 2: 118 (1920). REMARKS: The type materials of each of these three taxa contain several elements that display an intermediate appearence between H. angustifolium and H. italicum subsp. italicum, some being more similar to H. italicum and others to H. angustifolium, thus showing a gradual transition to both species. Past or present hybridization events may have been the cause of this morphological intermediacy, since H. italicum subsp. italicum and H. angustifolium are sympatric, or nearly sympatric, at these localities. 7. Helichrysum italicum (Roth) G. Don in Loudon, Hort. Brit. 342 (1830) : Gnaphalium italicum Roth in Bot. Mag. (Römer & Usteri) 4 (10): 19 (1790). NEOTYPE: (Georgiadou 1985, p. 888) ‘‘Gnaphalium italicum’’ B-W No. 15445!. DESCRIPTION: Sub-shrubby or shrubby perennials, arachnoid to densely tomentose, strongly aromatic, up to 60 cm high. Vegetative stems several, erect, leafy all their length, sometimes bearing axillary leaf fascicles; flowering stems several, erect, ascendent or decument, leafy all their length, more densely so basally. Lower and medial cauline leaves of the flowering and vegetative stems 2–37 mm  0.4–1.8, linear, subdecurrent, obtuse, concolorous or discolorous, subglabrous to tomentose and eglandular to sparsely glandular on the adaxial surface, densely tomentose and sparsely to densely glandular, rarely eglandular, on the abaxial surface, margin revolute, sometimes undulate. Lower and medial leaves of the flowering stems patent to erecto-patent, decreasing in size to the synflorescence; uppermost leaves appressed to the stem and more laxly arranged. Synflorescences corymbose, terminal, dense to rather lax and branched, 4.5–62 mm  3–80 mm, with 2–120 capitula, rarely solitary capitula. Capitula 4–6.5 mm  2–4(5) mm, cylindrical to narrowly campanulate (Figs. 2G, 2I, 2K), heterogamous or rarely homogamous, with 8–34 yellow florets; pistillate florets (0)1–10, hermaphroditic florets 8–31. Phyllaries 20–40, densely imbricate, papery except the outermost coriaceous, at least the proximal half; outermost phyllaries 1–3 mm  0.4–1.5 mm, totally coriaceous or rarely with the distal half papery, narrowly lanceolate, lanceolate, obovate # 2006 NRC Canada 1224 Can. J. Bot. Vol. 84, 2006 or ovate, acute or obtuse, completely tomentose, sometimes the inner face as well, or the proximal half tomentose and eglandular to densely glandular; middle phyllaries 3– 4.7 mm  1.4–2.8 mm, obovate, ovate or elliptic, acute or obtuse, stereome arachnoid and eglandular to sparsely glandular; innermost phyllaries 3–5.5 mm  0.5–1.3 mm, linear, narrowly lanceolate or narrowly oblanceolate, acute or obtuse, stereome glabrous to tomentose and sparsely to densely glandular; mean length of innermost phyllaries / mean length of outermost phyllaries 1.86–3.64; mean length of innermost phyllaries / mean length of middle phyllaries 0.96–1.21. (Fig. 4G, 4H, 4I). Receptacle flat, smooth or alveolate. Corolla of the pistillate florets 2.6–4 mm; corolla of the hermaphroditic florets 2.9–4.4 mm. Middle phyllaries length / mean length of the hermaphroditic florets 0.87–1.32. Cypselae 0.8–1.2 mm  0.3–0.7 mm, cylindrical to ovoid-cylindrical, with regularly scattered white duplex hairs, sometimes mixed with amber multicellular biseriate glandular hairs, rarely completely glabrous. Pappus bristles 2.7–4.2 mm long; apical cells acute. DISTRIBUTION: Central Mediterranean area, and scattered, isolated localities in North Africa in the west and Cyprus in the east. VARIABILITY: Helichrysum italicum is a very variable species, as would be expected from its wide distribution and the diverse habitats where it grows. Part of the observed variability is probably due to phenotypic plasticity, as is the case with other Helichrysum species, although part of the variability seems to be genetically determined. Such traits allow the recognition of three different and rather well-defined subspecific taxa (see Tables 2, 3), which are primarily distributed in well-defined, mostly allopatric areas. However, in some localities where the subspecies are partly sympatric, intermediate specimens are found, as would be expected since they belong to the same species and no reproductive barriers exist. TAXONOMIC AFFINITIES: This species is closely related to H. angustifolium and H. serotinum. See Taxonomic affinities sections under these two species. Key to the subspecies 1. Plants without axillary leaf fascicles; lower and medial cauline leaves of the flowering and vegetative stems (7)12–37 mm long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7a. subsp. italicum 1. Plants generally with axillary leaf fascicles on vegetative stems; lower and medial cauline leaves of the vegetative and flowering stems 2–21(29) mm long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Lower .... 2. Lower .... and medial cauline leaves of the vegetative and flowering stems (7)10–21 mm long, leaf margin not undulate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7b. subsp. siculum and medial cauline leaves of the vegetative and flowering stems 2–10(29) mm long, leaf margin generally undulate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7c. subsp. microphyllum 7a. Helichrysum italicum subsp. italicum = H. numidicum Pomel, Nouv. Mat. Fl. Atl. 2: 288 (1875). = H. italicum var. ericoideum Fiori in Fiori & Paol., Fl. Italia 3: 283 (1904). Calabria, Fossiata, Longobucco, Ponte di Cecita, granitico, 1100 m, 29-VII-1918, A. Fiori s.n. (FI!; isolectotypes: Calabria, Sila, in ditione Longobucco, loco Ponte di Cecita dicto, 1100 m, solo granitico, 3-VIII-1918, A. Fiori s.n. (Flora Italica exsiccata ser. III, No. 2570), BC 30991!, BM!, G!, K!, WU!). ILLUSTRATION: Sibthorp and Smith (1839, Table 857); Hegi (1915, p. 473, Fig. 239); Pignatti (1982, p. 42); Jeanmonod (1998, p. 130). DESCRIPTION: Plants up to 70 cm high, usually not bearing axillary leaf fascicles on the vegetative stems. Lower and medial cauline leaves of the flowering and vegetative stems (7)12–37 mm  0.4–1.8 mm, margin not undulate. Synflorescences 10–62 mm  18–80 mm, with 10–120 capitula. Cypselae with regularly scattered white duplex hairs. CHROMOSOME NUMBER: 2n = 28 (D’Amato 1971; Nilsson and Lassen 1971; Namur and Verlaque 1976). DISTRIBUTION: Widespread in Italy and Croatia, it extends also to the easter Mediterranean coast of France and Corsica, Bosnia–Herzegovina, Serbia and Montenegro, Slovenia, LECTOTYPE (DESIGNATED HERE): Greece, mainly Aegean islands, and Cyprus, as well as in scattered, isolated localities in Algeria, Morocco, and Tunisia. Davis and Kupicha (1975) cited it as doubtfully present in Turkey, and in fact we have not found any herbarium specimen collected in this country. Figure 9. HABITAT: It grows in a great diversity of open habitats, including several shrubby and herbaceous formations, road banks and path margins, maritime rocks, cliffs and sand dunes as well as on several types of substrate, granitic, schistose, volcanic, or limestone rocky soils. It is a very common species in its geographic area and is often one of the first pioneer species to colonize newly opened areas. Altitudinal range: 0–2200 m. PHENOLOGY: Flowers (May) June–August (September). VARIABILITY: Helichrysum italicum subsp. italicum is very variable, as would be expected from its wide distribution and the diversity of habitats where it grows. This variability extends to all its morphological characters, although certain deserve particular mention. This subspecies does not, in general, possess axillary leaf fascicles on its vegetative stems although, as in H. serotinum, some specimens do occasionally have them [Italy: Etruria, Prov. di Firenze, Vallombrosa, loco Bocca del Lupo dicto, 1200 m, 14-VIII-1909, Fiori s.n. (Flora Italica exsiccata series II Fiori & Béguinot 1165) (FI; K; WU)]. The plants belonging to this subspecies are normally rather tall, 40–70 cm, whereas some short specimens, only 10 cm high, can be found in mountain localities [Italy: # 2006 NRC Canada Galbany-Casals et al. Appenino Tosco-Emiliano, Sasso di Castro, 1260 m, 11VII-1966, Margheri s.n. (FI)]. Pomel (1875) described H. numidicum based on a plant from Khenchela, Algeria. After studying the type material of this taxon and some other specimens from Morocco [Dj. Bouachfal, tribu des Aı̈t Chitachen, Province de Demnat, 27VII-1879, Ibrahim s.n. (MPU; P)], we observed that all these North African specimens have the outermost phyllaries almost completely papery and the innermost ones with very scarce glandular hairs. As they resemble H. italicum subsp. italicum in all other morphological traits, we believe that, despite their differences, these specimens do not deserve any taxonomic recognition. In some localities where H. italicum subsp. italicum is partly sympatric with the other subspecies some intermediate specimens are found, and therefore the observed variability probably originates from gene flow between the pair of subspecies involved. On the one hand, in the regions of Calabria and Puglia, in southern Italy, some specimens among the studied material approximate subsp. siculum in their shorter than usual leaves for subsp. italicum and in bearing axillary leaf fascicles [Apulia Tarentum [Taranto], loco dicto Gravina di Leucaspide, 30 m, 14-VII-1914, Lacaita s.n. (Flora Italica exsiccata ser. III No. 2376) (BC 30990; FI; WU); Calabria, Sila, in ditione Longobucco, loco Ponte di Cecita dicto, 1100 m, 3-VIII-1918, Fiori s.n. (Flora Italica exsiccata ser. III, No. 2570) (BC 30991; BM; G; K; WU)]. However, we believe that the plants that grow in these regions generally fit better into H. italicum subsp. italicum’s variability. On the other hand, intermediate specimens between subsp. italicum and subsp. microphyllum, as regards plant height, leaf length and presence of axillary leaf fascicles on vegetative stems, are very frequent in areas where they co-occur. Particularly in southern Corsica, specimens exhibiting all the degrees of morphological variation between these two subspecies can be found. After examining several specimens from this area, we agree with Jeanmonod (1996), who studied this particular case in detail and postulated that gene exchange events, together with adaptation to difficult maritime ecological conditions (short and compact plants), determined the variability of phenotypes present in Corsica. Some of the intermediate specimens studied from Corsica are: lieux secs et incultes des terrains granitiques près d’Ajaccio, 10-XII-1852, Requien s.n. (K); Bastélica, 7-VII1878, Reverchon s.n. (K; WU); Bonifacio, les plages, 12VII-1880, Reverchon 305 (K); Bonifacio, VI-1911, Stefani s.n. (MPU); Bonifacio, VI-1914, Cousturier s.n. (BM); Ajaccio, Castelluccio, maquis le long de la route, 27-XI1916, Major s.n. (K); Bonifacio, terrains calcaires, VI-1919, Stéfani s.n. (MPU); Zonza, maquis en bordure de la route de Lévie, sur granite, 30-VII-1929, Litardière s.n. (BC 30900; BM; MA 425075). A similar situation is occurring on some islands of the Cyclades and Dodecanese archipelagos, where dwarf and densely tomentose specimens with short leaves and axillary leaf fascicles on the vegetative stems are found. While it is likely that part of this morphological aspect may reflect an adaptation to harsh ecological conditions such as maritime rocks and sand dunes exposed to the wind, we also believe it may reflect past gene flow with extinct populations of 1225 H. italicum subsp. microphyllum, as this subspecies is not growing at present in these islands. Subsp. microphyllum is common in Crete, however, and the distances are not so great as to prevent dispersal events between these islands. In Cyprus both subsp. italicum and subsp. microphyllum are found, as well as certain intermediate specimens. Some of the intermediate specimens we have studied are from the Cyclades archipelago [Ios, 29-VI-1889, Heldreich & Halácsy 4217 (G); Ios, 10-IV-1927, Rechinger fil. 251 (BM); Ios, 25-V-1972, Marius 1132 (MA 241541); Myconos, 4-VII1901, Heldreich 1643b (WU); Naxos, 26-VI-1889, Heldreich s.n. (K); Syros, Orphanides 1144 (BM; E; G; K; P; WU)]; the Dodecanese Islands [Ikaria, 2-VIII-1887, Major 934 (G; P); Icaria, VI-1933, Guiol 191 (FI)]; and Cyprus [pr. monast. Kikku, 5-VII-1880, Sintenis & Rigo 797 (G; K; WU); Stavroni area, 26-VI-1932, Syngrassides 395 (K)]. NOMENCLATURAL REMARKS: Fiori (1904) described H. italicum var. ericoideum from Calabria, Sicily and Lipari. After studying numerous herbarium specimens from these regions, we believe that this taxon comprises several species, as the plants from Calabria correspond to H. italicum subsp. italicum, those from Sicily to H. italicum subsp. siculum, and those from Lipari to H. angustifolium. As we are designating as lectotype a specimen from Calabria, this taxon becomes a synonym of H. italicum subsp. italicum. 7b. Helichrysum italicum subsp. siculum (Jord. & Fourr.) Galbany, L. Sáez & Benedı́ comb. nov. : H. siculum Jord. & Fourr., Brev. Pl. Nov. 2: 67 (1868) [basyonym]. Sicile, 1849, Gussone s.n. [ex herb. Al. Jordan 187] (LY photo!; isolectotype: MPU!). ILLUSTRATION: Fig. 8B. DESCRIPTION: Plants up to 40 cm high, bearing axillary leaf fascicles on the vegetative stems. Lower and medial cauline leaves of the flowering and vegetative stems (7)10– 21 mm  0.6–1 mm, margin not undulate. Leaves of axillary fascicles 2–3 mm  0.6–1 mm. Synflorescences 6– 20 mm  12–25 mm, with 3–42 capitula. Cypselae with regularly scattered white duplex hairs. CHROMOSOME NUMBER: 2n = 28 (D’Amato 1971). DISTRIBUTION: Endemic to Sicily (Fig. 9). HABITAT: This subspecies grows in a great diversity of open habitats, including several shrubby and herbaceous formations, road banks and path margins, beds of dried-up streams, maritime rocks and sand dunes; as well as on several types of substrates, such as volcanic and limestone rocky soils. It is often one of the first pioneer species to colonize newly opened areas. Altitudinal range: 0–1300 m. PHENOLOGY: Flowers (May) June–August (September). VARIABILITY: Morphologically, this subspecies is well characterized: it always has the adaxial surface of leaves greenish, subglabrous to arachnoid, not as tomentose as is usual in H. italicum subsp. italicum; the leaves of vegetative stems are noticeably shorter than those of flowering stems; and it nearly always possesses axillary leaf fascicles on vegetative stems. Moreover, H. italicum subsp. italicum normally has longer leaves (see Tables 2, 3), and larger synflorescences LECTOTYPE (DESIGNATED HERE): # 2006 NRC Canada 1226 Can. J. Bot. Vol. 84, 2006 Fig. 9. Distribution of Helichrysum serotinum subsp. serotinum (H. ser subsp. ser), H. serotinum subsp. picardii (H. ser. subsp. pic), Helichrysum italicum subsp. italicum (H. ita subsp. ita), H. italicum subsp. microphyllum (H. ita subsp. micro) and H. italicum subsp. siculum (H. ita subsp. sic), and intermediate specimens (interm spec) of H. serotinum subsp. serotinum and Helichrysum stoechas (H. stoe), H. serotinum subsp. picardii and H. stoechas, H. italicum subsp. italicum and H. stoechas, H. italicum subsp. microphyllum and H. stoechas, and H. italicum subsp. siculum and H. stoechas. with more numerous capitula, than H. italicum subsp. siculum and H. italicum subsp. microphyllum, although this second character is rather variable and cannot be used in a key. H. italicum subsp. microphyllum may also have the adaxial surface of leaves subglabrous or arachnoid and often bears axillary leaf fascicles, as H. italicum subsp. siculum, although its leaves are noticeable shorter than those of H. italicum subsp. siculum. Moreover, leaf margins are often undulate in H. italicum subsp. microphyllum and not in H. italicum subsp. siculum. Despite this generally strong characterization of H. italicum subsp. siculum, it presents some variability and certain specimens do not exhibit axillary leaf fascicles, thus approximating H. italicum subsp. italicum [Italy: Sicily, propè Randazo, 5-VII-1855, E. & A. Huet du Pavillon s.n. (BM; FI; G; K; W); Sicily, in latere occidentali montis Aetnae prope Bronte versus flumen Giaretta, 2-VII-1874, Gabriel Strobl s.n. (BM); Sicily, Giampilieri, halfway from Messina to Taormina, 5 m, 2-VI-1972, Stace & Cotton 550 (BM); Sicily, Misilmeri, VI, Todaro 548 (BM; FI; MPU)]. We propose the recognition of this taxon at subspecies level, as we believe it to be morphologically well characterized, with a well-defined geographic distribution, allopatric with that of other subspecies of H. italicum. We designate as lectotype a specimen at LY and as isolectotype a specimen at MPU. NOMENCLATURAL REMARKS: 7c. Helichrysum italicum subsp. microphyllum (Willd.) Nyman, Consp. Fl. Eur. 1: 382 (1879) : Gnaphalium microphyllum Willd., Sp. Pl. 3: 1863 (1803). (Galbany-Casals et al. 2006, p. 492) B-W No. 15448-01 photo!. LECTOTYPE: ILLUSTRATION: Gamisans (1991, p. 88); Jeanmonod (1998, p. 136). Plants up to 30(40) cm high, generally bearing axillary leaf fascicles on vegetative stems. Lower and medial cauline leaves of the flowering and vegetative stems 2– 10(29) mm  0.4–1.5 mm, margin often undulate. Leaves of axillary fascicles 1–6.5 mm  0.3–1.2 mm. Synflorescences 4.5–40 mm  3–44 mm, with 2–64 capitula, capitula rarely solitary. Cypselae with regularly scattered white duplex hairs, sometimes mixed with amber, multicellular, biseriate glandular hairs, rarely completely glabrous. CHROMOSOME NUMBER: 2n = 28 (Contandriopoulos 1962; D’Amato 1971). DISTRIBUTION: It has a distribution disjunct between the Mediterranean islands of Majorca, Corsica, Sardinia, Crete, and Cyprus. Figure 9. HABITAT: Like the other two subspecies, H. italicum subsp. microphyllum grows in a wide variety of open habitats, although it favors particular habitats depending on the island where it grows. On Majorca and Crete, it is found mostly in mountain open shrubby formations, while remaining uncommon in either the lowlands or on coastal sand dunes or maritime rocks. This habitat preference may result from the widespread presence of H. stoechas in these lowland and coastal habitats, which may be better adapted to such ecological conditions. This hypothesis is supported by the fact that H. stoechas is not present in Sardinia where, in contrast, H. italicum subsp. microphyllum is widespread, occupying diverse open habitats, including mountain shrubby formations, road banks and path margins, maritime rocks and sand dunes. Altitudinal range 0–1950 m. PHENOLOGY: Flowers (May) June–September (October). DESCRIPTION: VARIABILITY: Helichrysum italicum subsp. microphyllum is the # 2006 NRC Canada Galbany-Casals et al. most variable subspecies, probably due to its disjunct distribution among several islands. Plants growing in mountain localities from Majorca are greenish, often lack axillary leaf fascicles and have very short leaves, often less than 6 mm long, quite appressed to the flowering stem. However, some larger specimens with a tomentose indumentum are also found in lowland localities (on Dragonera island, off the west coast of Majorca). Plants growing in mountain localities in Crete are similar to those of Majorca: greenish with very short leaves, although the leaves of flowering stems are patent to erecto-patent, not appressed, and always bear axillary leaf fascicles. On these two islands, plants are shorter and have a more compact habit the higher they grow. In Corsica and Sardinia, plants of H. italicum subsp. microphyllum are always whitish, always bear numerous axillary leaf fascicles, and have densely tomentose leaves. The general aspect is so different from those in Crete and Majorca that one can guess their provenance after only a quick look. From our point of view, however, indumentum is far too variable, as with nearly all Helichrysum species, and no other constant morphological difference can be observed allowing taxonomic differentiation. With regards to the habit, these plants from Corsica and Sardinia are dwarf and compact, with very short leaves, particularly when growing in coastal localities where ecological conditions are harsh, or they are tall with rather long leaves when they grow inland or are protected from the wind by taller vegetation. In Corsica, intermediate specimens with H. italicum subsp. italicum can be observed in areas where both subspecies are sympatric, consisting of rather tall plants with long leaves and axillary leaf fascicles (see H. italicum subsp. italicum Variability). In Sardinia, some tall specimens without axillary leaf fascicles can be found [arrondissement de Tempio, 2-VII-1882, Reverchon s.n. (Plantes de Sardaigne 96) (G; K; MA 125128); Monte Narba, Sarrabus, 15-V-1895, Gestro s.n. (FI); Da Carreboi a Fomi, 28-VI-1898, Martelli s.n. (FI); Campeomu e Valle di Riu Conventu, 15-V-1946, Martinoli s.n. (FI); Tempio, carretera d’ascenció al Monte Limbara, 900 m, 30-VI-2002, Galbany & Sáez s.n. (BCN 20578)]. Because of these morphological traits, these specimens also resemble subsp. italicum, but we cannot be certain whether this reflects past gene exchange with this subspecies, as H. italicum subsp. italicum is not present in Sardinia, or if it only reflects the morphological variability of H. italicum subsp. microphyllum. Capitula width and the presence/absence of glandular hairs on the outermost phyllaries usually have been used to differentiate H. italicum subsp. italicum and H. italicum subsp. microphyllum (Clapham 1976; Pignatti 1982). The capitula width is not noticeably different in these two subspecies (see Table 2). Moreover, the glandulosity of the outermost phyllaries is a highly variable trait within each subspecies, both subspecies being eglandular or sparsely to densely glandular, as is H. italicum subsp. siculum. In conclusion, as Jeanmonod (1996, 1998) stated, these two characters are not useful in differentiating the subspecies of H. italicum. Specimens of H. italicum subsp. microphyllum often have undulate leaf margins, though some specimens do not [France: Corsica, Golfe de Santa Manza, plage de Maora, 2-VI-1997, Lambinon 97/Co/117 & Van Den Sande (MA 595752); Corsica, Bonifacio, Cabo Pertusato, cra. a 1227 Playa Piantarella, 6-VI-2002, Nieto 4506 & Fuertes (BCN 20713); Italy: Sardinia, Tempio, carretera al Monte Limbara, 900 m, 30-VI-2002, Galbany & Sáez s.n. (BCN 20578)]. In H. italicum subsp. microphyllum, as in the other two subspecies of H. italicum, cypselae have regularly arranged white duplex hairs on the epidermis. However, some specimens may have glabrous cypselae [France: Corsica, Porto Pozzo, playa de Porto Liscia, 7-VI-2002, Nieto 4529 & Fuertes (BCN 20718); Italy: Sardinia, entre Porto Torres i Castelsardo, dunes de la platja Platamone, 29-VI-2002, Galbany & Sáez s.n. (BCN 20738; BCN 25235); Sardinia, Capo Carbonara, 1-VII-2002, Galbany & Sáez s.n. (BCN 20709)]. Some others have amber, multicellular, biseriate glandular hairs mixed with the duplex hairs in various proportions (Fig. 1c) [Spain: Majorca, Serra de Tramuntana, Coll de Ses Cases de Neu, 1200 m, 21-VI-2001, Galbany & Sáez s.n. (BCN 6115; BCN 20580; BCN 25236); Coma des Nevaters, 1100 m, VIII-2001, Sáez 5739 (BCN 20710)]. This is the first time that this type of hair has been reported from the cypselae epidermis of a species from H. sect. Stoechadina, and it has only been observed in a few specimens of subsp. microphyllum from some Majorcan populations. In contrast, this type of multicellular hair is not uncommon on the cypselae of H. sect. Helichrysum species. Hybrids H. italicum subsp. italicum  H. stoechas REMARKS: Some hybrid specimens between these two taxa have been observed at several localities on the western Italian coast where the taxa co-occur. These specimens have broadly campanulate capitula like those of H. stoechas, and partly coriaceous outermost phyllaries, like those of H. italicum. H. italicum subsp. siculum  H. stoechas REMARKS: We have studied one intermediate specimen between these two taxa from northwestern Sicily. This specimen has broadly campanulate capitula like those of H. stoechas, and linear-lanceolate outermost phyllaries, acute and partly coriaceous, like those of H. italicum. H. italicum subsp. microphyllum  H. stoechas REMARKS: Some hybrid specimens between these two taxa were observed at several localities in Majorca. These specimens have campanulate capitula like those of H. stoechas, and partly coriaceous outermost phyllaries like those of H. italicum. They usually have a tomentose indumentum, leaf margins that are not undulate, and axillary leaf fascicles. H. italicum subsp. microphyllum  H. rupestre We studied eight specimens at several localities in Sardinia, which exhibit some degree of intermediacy between these two taxa, once again reflecting the existence of introgressive events. In general, these plants are rather robust, with shorter leaves than those of H. rupestre but longer than those of H. italicum subsp. microphyllum. Moreover, they sometimes have axillary leaf fascicles, and they have narrower capitula than those of H. rupestre, similar to those of H. italicum subsp. microphyllum although not so densely glandular. REMARKS: # 2006 NRC Canada 1228 Baccheta et al. (2003) described H. saxatile subsp. morisianum from southern Sardinia. They distinguished it from H. saxatile subsp. saxatile (H. rupestre under the present taxonomic treatment) based on several morphological characters: H. saxatile subsp. morisianum having leaves 1.5–2.2 mm wide, capitula 5–6 mm wide, corolla 3.5–4 mm long, pappus 3–3.2 mm long, cypselae 0.7–0.8 mm long with sparse duplex hairs; and H. saxatile subsp. saxatile having leaves 3.5–4 mm wide, capitula 6–8 mm wide, corolla 4–4.5 mm long, pappus 3.5–4 mm long, cypselae 0.9–1 mm long with densely arranged duplex hairs. Based upon our biometric study of numerous H. rupestre specimens from Sardinia and the entire distribution, we noted that the ranges of all these characters, from both taxa, are included within the intraspecific variability of H. rupestre. However, we think it probable that H. saxatile subsp. morisianum is based on hybrid specimens between H. italicum subsp. microphyllum and H. rupestre, which would explain the slightly narrower capitula. Moreover, we have observed one presumably hybrid specimen between these two species from the type locality of H. saxatile subsp. morisianum. As we have not studied any type material of this taxon, we cannot ascertain its true identity at the present time. 8. Helichrysum serotinum (DC.) Boiss., Voy. Bot. Espagne 2: 327 (1839) : H. italicum subsp. serotinum (Boiss.) P. Fourn., Quatre fl. France: 952 (1939). HOLOTYPE: In regni di Granada partibus interioribus alt. 2000– 4500’, 1838, Boissier s.n. (G-DC photo!; isotype: Regnum granatense, sur les p.es de montagn, floret en aout et fins de juillet, partibus meridionales Sa Nevada, VIII-1837, Boissier s.n., G!). DESCRIPTION: Shrubby perennials, arachnoid to densely tomentose, very aromatic, up to 50 cm high. Vegetative stems several, erect, ascendent or decument, leafy all their length, rarely bearing axillary leaf fascicles; flowering stems several, erect, ascendent or decument, leafy all their length, more densely so basally. Lower and medial cauline leaves of the flowering and vegetative stems 10–57 mm  0.5– 2 mm, linear, subdecurrent, obtuse to completely rounded, concolorous or discolorous, subglabrous to tomentose and eglandular to sparsely glandular on the adaxial surface, densely tomentose and densely glandular on the abaxial surface, margin revolute, not undulate. Lower and medial cauline leaves of the flowering stems patent to erecto-patent, decreasing in size to the synflorescence; uppermost leaves appressed to the stem and more laxly arranged. Synflorescences corymbose, terminal, dense to rather lax and branched, 10–61 mm  16–85 mm, with 7–252 capitula. Capitula 4–7.5 mm  2–5 mm, cylindrical to narrowly campanulate (Figs. 2H, 2J), heterogamous, rarely homogamous, with 7–36 yellow florets; pistillate florets (0)1–9, hermaphroditic florets 5–30. Phyllaries 20–46, densely imbricate, papery except the outermost coriaceous; outermost phyllaries 0.8–3 mm  0.4–1.4 mm, totally coriaceous, rarely with the distal half papery, linear-lanceolate, lanceolate or narrowly triangular, acute, rarely obtuse, completely tomentose, sometimes the inner face as well, and eglandular to sparsely glandular; middle phyllaries 2.5–5.5 mm  1.3–3 mm, obovate, ovate or elliptic, acute or obtuse, stereome arachnoid and Can. J. Bot. Vol. 84, 2006 eglandular to sparsely glandular; innermost phyllaries 3– 5.8 mm  0.4–1.5 mm, linear, narrowly lanceolate or narrowly oblanceolate, acute or obtuse, stereome glabrous to arachnoid and densely glandular; mean length of innermost phyllaries / mean length of outermost phyllaries 1.47–3.73; mean length of innermost phyllaries / mean length of middle phyllaries 0.96–1.19. (Figs. 4J, 4K). Receptacle flat or concave, smooth or alveolate. Corolla of the pistillate florets 2.5–4.5 mm; corolla of the hermaphroditic florets 3– 4.9 mm. Middle phyllaries length / mean length of the hermaphroditic florets 0.89–1.27. Cypselae 0.9–1.4 mm  0.35– 0.7 mm, cylindrical to ovoid-cylindrical, glabrous. Pappus bristles 2.7–4.5 mm long; apical cells obtuse. Western Mediterranean, in the Iberian Peninsula, the Balearic Islands (Ibiza), southern France, northern Algeria, and northern Morocco. DISTRIBUTION: TAXONOMIC AFFINITIES: Helichrysum serotinum is closely related to H. angustifolium and H. italicum. Helichrysum angustifolium and H. serotinum resemble each other in habit and in the shape and structure of their capitula. However, H. angustifolium is more robust, in general, and has longer leaves and slightly smaller capitula than H. serotinum. Moreover, H. serotinum has glabrous cypselae whereas those of H. angustifolium have regularly scattered duplex hairs. Several authors (Clapham 1976; Devesa 1987; Bolòs and Vigo 1996) considered H. italicum to be conspecific with H. serotinum, accepting the latter at the subspecific level under H. italicum. In fact, these two species are very similar, both in terms of their habit and in the morphology of their capitula. However, they differ in two qualitative characters: (1) the presence or absence of duplex hairs on the cypselae epidermis, H. serotinum never having duplex hairs on the cypselae, whereas H. italicum nearly always having regularly scattered duplex hairs; and (2) the shape of cells at the apex of the pappus bristles, which are acute in H. italicum, but obtuse in H. serotinum. It remains quite difficult to identify valid qualitative morphological traits to distinguish species in H. sect. Stoechadina since they are all very similar and closely related. We believe that these characters, as they are strongly maintained, justify the classification of these two taxa as different species. NOMENCLATURAL REMARKS: de Candolle (1838: 299) noted of the plants collected by Boissier: ‘‘H. stoechas var.? serotinum, caule parcius lanuginoso. In regni Granatensis partibus interioribus alt. 2000-4500 ped. legit cl. E. Boissier. H. serotinum Boiss.! ined. Differt ab H. Staechade vero florescentiâ seriori nempè aug. et septembri et foliis inodoris. (v. s.)’’. Boissier (1839) not in references who finally raised this taxon to the rank of a species, as H. serotinum, said that it was widely distributed in the Mediterranean area. This suggests to us that his concept of H. serotinum was equivalent to the current concept of H. italicum, his H. serotinum var. occidentale corresponding to the current concept of H. serotinum; his H. serotinum var. orientale corresponding to H. italicum subsp. italicum; and his H. serotinum var. microphyllum corresponding to the same taxon currently accepted at subspecific level, H. italicum subsp. microphyllum. Nowadays it is accepted that H. serotinum (DC.) Boiss. is present only in the Iberian Peninsula (Spain and Portugal), northern Morocco, northern Algeria and southern France. # 2006 NRC Canada Galbany-Casals et al. 1229 Key to the subspecies 1. Capitula (2.5)3–5 mm wide in its medial part, with (14)16–36 florets . . . . . . . . . . . . . . . . . . . . 8a. subsp. serotinum 1. Capitula 2–3.5(4.5) mm wide in its medial part, with 7–22(26) florets . . . . . . . . . . . . . . . . . . . . . 8b. subsp. picardii 8a. Helichrysum serotinum subsp. serotinum ILLUSTRATION: Devesa (1987: 36); Bolòs and Vigo (1996: 738). DESCRIPTION: Capitula 4.5–7.5 mm  (2.5)3–5 mm, with (14)16–36 yellow florets; pistillate florets (0)3–9, hermaphroditic florets (10)13–30. Corolla of the pistillate florets 2.9–4.5 mm long; corolla of the hermaphroditic florets 3.4– 4.9 mm long. CHROMOSOME NUMBER: 2n = 28 (Lorenzo-Andreu and Garcı́a Sanz 1950). DISTRIBUTION: Iberian Peninsula, Balearic Islands (Ibiza), southern France, and one locality in Algeria (Fig. 9). HABITAT: Open areas, clearings in shrubby communities, road banks and abandoned cultivated areas, on rocky limestone soils and occasionally in gypsaceous or siliceous soils. Altitudinal range: 0–2080 m. PHENOLOGY: Flowers (January) June–September (November). The occasional specimens observed flowering in winter still preserved the dried summer main synflorescences or (and) had only a very weak winter flowering [Spain: Murcia, Lorca, Cabecico de La Cantera, 25-I-1965, Novo & Valdés s.n. (SEV 7487); Zaragoza, La Almunia, Mularroya, Rı́o Grio, 11-XI-1975, P. Montserrat s.n. (JACA 609875); Navarra, Tudela, Balsa de Agua Salada, 6-XI-1988, Aizpuru & Catalán s.n. (ARAN 20437)]. VARIABILITY: In general, it is a rather tall plant with long arachnoid leaves, although we have observed, both in the field and on herbarium sheets, short specimens with noticeably shorter leaves and a denser indumentum, particularly from mountain localities on poor rocky soils, such as in Sierra de las Nieves [Spain, Málaga, Yunquera, pinsapares de la Nava, 24-VIII-1976, Hernández s.n. (COA 9632)]. Although this species does not usually bear axillary leaf fascicles, we have observed, both in the field and on some herbarium sheets, specimens that occasionally have them on vegetative stems, particularly in winter [Spain: Zaragoza, La Almunia, Mularroya, Rı́o Grio, 11-XI-1975, P. Montserrat s.n. (JACA 609875); Tarragona, Coves d’en Pere, prop del cim del Tossal de la Baltasana, 1-I-2004, M. Galbany & S. Arrabal s.n. (BCN 20895)]. 8b. Helichrysum serotinum subsp. picardii (Boiss. & Reut.) Galbany, L. Sáez & Benedı́ comb. nov. : Helichrysum picardii Boiss. & Reut. in Boiss., Diagn. Pl. Orient. ser. 2, 3 (6): 103 (1859) [basyonim]. (Galbany-Casals et al. 2006, p. 492) Sables maritimes au Coto près Puerto Santa Marı́a, 20-VII-1849, E. Bourgeau 317 (G!; isolectotypes: BM!, E!). ILLUSTRATION: Devesa (1987: 36). DESCRIPTION: Capitula 4–6.5 mm  2–3.5(4.5) mm, with 7– LECTOTYPE : 22(26) florets; pistillate florets (0)1–7(9), hermaphroditic florets 5–17(18). Corolla of the pistillate florets 2.5–4 mm long; corolla of the hermaphroditic florets 3–4.5 mm long. 2n = 28 (Fernandes and Queirós 1971; Queirós 1980; Valdés-Bermejo 1980; Lago and Castroviejo 1993). CHROMOSOME NUMBER: Western coast of the Iberian Peninsula and northern Morocco (Fig. 9). DISTRIBUTION: HABITAT: Maritime sandy soils. Altitudinal range: 0–30 m. Flowers (March) June–August (December). As in the case of H. serotinum subsp. serotinum, the occasional specimens observed flowering in winter still preserved the dried, summer main synflorescences and underwent only a very weak winter flowering [Spain: Huelva, Almonte, Reserva Biológica de Doñana, Sabinar del Tı́o Pulga, 18-XI-1972, B. Cabezudo s.n. (SEV 17332)]. PHENOLOGY: VARIABILITY: This is a variable taxon, particularly with regard to the density of the indumentum and the habit. While specimens with arachnoid, greenish leaves have been recognised at several subspecific levels [H. picardii var. virescens Valdés Berm., H. picardii subsp. virescens (Valdés Berm.) Rivas Mart.], we believe, after studying numerous representative specimens, that this variability reflects phenotypic plasticity and thus does not deserve taxonomic recognition. Helichrysum serotinum subsp. picardii specimens are mainly ascendent or decumbent, reflecting an adaptation to the extreme ecological conditions where they grow, such as maritime sand dunes. However, several specimens collected also in this habitat exhibit an erect habit [Portugal: Algarve, Manta Rota, 3-VI-1985, Moura 2797 (COI; MA 419073; MA 419126); Baixo Alentejo, 19-VI-1962, Rozeira & al. s.n. (PO 25331); Baixo Alentejo, Sines, junto à praia de Monte Velho, 7-VIII-1979, Barbosa 13256 (LISU); Beira Litoral, arredores da Figueira da Foz, Gala, IX-1882, Moller s.n. (COI); Pinhal de Leiria, VIII-1884, Pimentel s.n. (COI); Ria de Aveiro, na Barra pr. da ponte da Barra, 24-VIII-1967, Ormonde & Rodrigues 207 (COI)], which may stem from the protective vegetation of their environment, as has also been observed for the very variable H. stoechas. In fact, we studied one collection that contained both tall erect and short decumbent specimens from the same gathering [Portugal: Lisboa, Cascais, entre Oitavos e O Guincho, 10-VII-1953, Mendes & Romariz 47 (COI; LISU; MA 241544)], effectively proving that the habit of this taxon mainly reflects local ecological conditions. The size of the synflorescences is very variable as well, though it is not correlated with the decumbent or erect habit, as short decumbent plants may have very large synflorescences. Despite this variability in both the habit and size of the synflorescences, the size of the capitula is not as variable. Capitula are, on average, significantly narrower and with fewer florets than those of H. serotinum subsp. serotinum # 2006 NRC Canada 1230 (see Table 3), which mainly distinguishes the two subspecies. Finally, while Helichrysum serotinum subsp. picardii does not usually bear axillary leaf fascicles, we have observed, on some herbarium sheets, specimens that occasionally present them on vegetative stems, particularly during winter [Spain: Huelva, Almonte, Reserva Biológica de Doñana, Sabinar del Tı́o Pulga, 18-XI-1972, Cabezudo s.n. (SEV 17332)]. NOMENCLATURAL AND TAXONOMIC REMARKS: Boissier and Reuter (1859) described H. picardii at the species level. This species has been recognised in some regional floristic treatments (Devesa 1987). In another floristic treatment covering a larger territory this taxon did not even appear (Clapham 1976). We propose a new combination for this taxon as a subspecies of H. serotinum due to the similarity of all qualitative characters, including the absence of duplex hairs on the cypselae surface, the trait that identifies them as a unique species and, at the same time, distinguishes them from other closely related species. Hybrids H. serotinum subsp. serotinum  H. stoechas Helichrysum mixtum Font Quer in Mem. Mus. Ci. Nat. Barcelona, Ser. Bot. 1 (2): 14 (1924), nom. illeg., non O. Hoffm. in Kuntze, Revis. Gen. Pl. 3 (2): 152 (1898). REMARKS: Helichrysum mixtum was described as a hybrid between H. stoechas and H. serotinum. We believe that the type specimen is, effectively, an intermediate specimen between these two species. Based on our field observations, however, these hybrids seem to have originated several independent times in several localities, as a result of punctual hybridization events, wherever both potential parental species grow together, but without constituting stable populations. In general, the flowering time of both parental species is separate, as H. stoechas mainly flowers in May-June whereas H. serotinum primarily flowers from late June to August. However, both flowering times partly overlap, easily permitting hybridization. Hybrids between H. stoechas and H. serotinum can be recognized by their intermediate phenology and some intermediate morphological characters, including capitula as narrow as those of H. serotinum but with the outermost phyllaries glabrous and papery, or not completely coriaceous, and cypselae bearing very few, or lacking, duplex hairs. H. serotinum subsp. picardii  H. stoechas We have studied two intermediate specimens between these two taxa, which have similar morphological characters as those hybrids between H. serotinum subsp. serotinum and H. stoechas. REMARKS: Acknowledgements The authors thank everyone who kindly provided material from their own field collections and the curators of all the herbaria visited and consulted. Also many thanks to A. Herrero and A. Méndez for kindly helping in some literature searches, to A. Herrero again and to J. McNeill for nomenclatural advice. Many thanks to the Scanning Electron Microscope staff (Serveis Cientı́fico-Tècnics UB). Thanks Can. J. 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