Porana nutans

Nomenclature

Accepted name/Authority/Place of publication:

Porana nutans (Moç. & Sessé ex Choisy) O’Donell, Lilloa 30: 62 (1960). – Ipomoea nutans Moç. & Sessé ex Choisy in DC., Prodr. 9: 368 (1845). – Calycobolus nutans (Moç. & Sessé ex Choisy) D.F.Austin, Ann. Missouri Bot. Gard. 58: 244 (1971). TYPE. Mexico. unpublished plate by Sessé & Moçiño (lecto G!, designated by Staples (2006: 456); copy US!)

Synonyms:

Dufourea? velutina M.Martens & Galeotti , Bull. Acad. Sci. Bruxelles 12(2): 259 (1845). – Prevostea? (Dufourea?) velutina (M.Martens & Galeotti) Walp., Repert. Bot. Syst. 6: 742 (1846). – Porana velutina (M.Martens & Galeotti) Hallier f., Bot. Jahrb. Syst. 16: 538 (1893). – Turbina velutina (M.Martens & Galeotti) Roberty, Candollea 14: 26 (1952). – Calycobolus velutinus (M.Martens & Galeotti) House, Bull. Torrey Bot. Club 34: 144 (1907). – TYPE. Mexico. “sur la route de Tehuacan à Oaxaca, près de la Venta de Aragon, à 3000 pieds, iv 1840,” Galeotti 1380 (lecto BR!, sheet 2˚ designated here; isolecto BR! [sheet 1˚], G!, P!, W!).

Breweria mexicana Hemsl., Biol. Centr.-Amer. Bot. 2: 400 (1882). – Turbina mexicana (Hemsl.) Roberty, Candollea 14: 26 (1952). – TYPE. Mexico. [Oaxaca] Sierra San Pedro Nolasco, 1843–1844, Jurgensen 623 (holo K!; iso BM! G!, G-BOIS!).

Breweria mexicana Hemsl. var. floribunda Villada, Naturaleza (Mexico City) ser. 2, 2: 127. tab. 7 (1892). – TYPE. Mexico, [Guerrero] montañas de Cacahuamilpa, Villada s.n. (lectotype: the plate in the protologue).

Calycobolus pringlei House, Bull. Torrey Bot. Club 34: 145 (1907). – TYPE. Mexico. Morelos: Yautepec, 21 Nov 1903, Pringle 8751 (holo US; iso BM, E, G(×4), GH, HBG, K, L(×3), M, MO, NSW, NY, S, UC).

Description

Habit:

Lianas or scandent shrubs; stems twining, 3–10 m long, base 0.5–8 cm diam., striate, older ones greyish brown, lenticellate; all axial parts varying from glabrous to tomentose with yellowish or ferruginous hairs.

Leaves:

Leaf petioles 2–18 mm long; blades lanceolate, ovate, or elliptic, 10–75 mm long, 4–50 mm wide, base rounded, obtuse, or truncate, apex usually attenuate or acute to obtuse and apiculate, glabrous or nearly so to tomentose on both sides, indumentum yellowish to reddish; lateral veins 5 or 6 per side.

Inflorescences:

Inflorescence peduncles 3–30 mm long; bracts shaped like leaves only smaller; pedicels 8–13 mm long; bracteoles filiform, 0.6–3 mm long, deciduous.

Flowers:

Flower sepals very unequal, outer 2 larger, ovate to elliptic, 8–14 mm long, 5.5–8 mm wide, base abruptly narrowing into oblong claw, apex rounded or retuse, mucronulate, outside glabrescent or finely velutinous especially near base, third sepal asymmetrical, as long as outer 2 but 4–5 mm wide, base lobed on one side, apex obtuse to rounded, mucronulate, inner 2 sepals tightly sheathing corolla base, broadly elliptic, trapezoidal, or transversely elliptic, 3–4 mm long, 4–5 mm wide, apex broadly rounded or truncate, mucronate, tomentose abaxially along middle, margins broadly hyaline, glabrous; corolla funnelform, tube broad, 13–17 mm long, pure white or yellowish white, limb flaring, bluntly 5-lobed, interplicae puberulent outside; stamens subequal, 13–15 mm long, filaments densely hairy around insertion, glabrous and free above, anthers broadly oblong, 2.5–3 mm long, white; pistil seated on an orange nectary disc, ovary globose-ellipsoid, incompletely 2-locular, 4-ovulate, densely pubescent, style branched, 1.2–1.5 cm long, fused below middle and pubescent, above 2-branched, arms unequal, glabrous, stigmas capitate-globose.

Fruits:

Fruiting sepals accrescent, spreading at maturity, outer 2 sepals 10–20 mm long, obovate, base abruptly narrowed, clawed, blade ovate to broadly elliptic, third sepal asymmetrical, 10–18 mm long, 2 inner 5–7 mm long, apiculate, all sepals chartaceous, venose, glabrescent to finely puberulent outside. Utricles broadly ellipsoid to globose, 5–9 mm long, 4–7 mm wide, papery, straw-yellow to reddish, tomentellous.

Seeds:

Seed broadly ellipsoid, 4–6 mm long, black-brown, glabrous; hilum basal, D-shaped or nearly circular.

Author:

Staples, G.W. & D.F. Austin.

References:

Staples, G.W. & D.F. Austin. 2009. Revision of neotropical Calycobolus and Porana (Convolvulaceae). Edinb. J. Bot. 66: 133–153.

Biogeography, Ecology and Natural History

Distribution Map:

Distribution:

Mexico, highlands of Colima, Guerrero, México, Michoacán, Morelos, Oaxaca, and Puebla. (map).

Ecology:

Reported from a
variety of habits such as deciduous forest (selva baja caducifolia),
disturbed tropical deciduous forest, desert thorn forest, laderas cerro
yesoso, rocky hills, hot barranca, dry river bed, streambanks, and steep
hills near the Pacific coast, among vegetational associates including Bursera, Ceiba, Cordia, Haematoxylum, Ipomoea, and Pseudosmodingium. Soil types have been
noted as rocky, limestone hills, and gypsum area. Elevation: 150–1,650 m.

Phenology:

Months

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flowering specimens

–

Fruiting specimens

–

Author:

Staples, G.W. & D.F. Austin.

References:

Staples, G.W. & D.F. Austin. 2009. Revision of neotropical Calycobolus and Porana (Convolvulaceae). Edinb. J. Bot. 66: 133–153.

Other information

Infraspecific Characters:

As the lengthy synonymy attests, Porana nutans is a variable species in several characters, particularly the trichome density and coloration, leaf size, and flower size and abundance. We have adopted a broad taxonomic concept that accommodates the observed phenotypic variability in one species; perhaps field study of living plants will enable recognition of infraspecific variants but at the current level of knowledge, based solely on herbarium material, we do not think it appropriate to recognise subspecies or varieties.

Authorship for webpage

Editor:

George Staples, Esmond Er

Contributors:

Classification:

Porana nutans

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