Flora of the Venezuelan Guayana
37. TYNANTHUS Miers, Proc. Roy. Hort. Soc. London 3: 193. 1863.
Lianas, the branchlets terete to subtetragonal, without interpetiolar glandular fields, often with a ridge between opposite petioles; pseudostipules lacking or foliaceous; often with a clove odor vegetatively. Leaves 2- or 3-foliolate; terminal leaflet often replaced by a simple or trifid tendril. Inflorescence an open or contracted axillary or terminal panicle. Calyx small, cupular, subtruncate, usually 5-denticulate; corolla white, often tiny, ± funnel-shaped, bilabiately split about half its length, puberulous outside. Anthers glabrous, subexserted, the thecae divaricate, bent at the middle and reflexed forward. Ovary conical, densely puberulous; ovules 2-4-seriate in each locule. Fruit a ± compressed linear capsule, the valves parallel to the septum, flat with a slightly or conspicuously raised margin. Seeds flat, 2-winged with hyaline-membranous wings.
Mexico, Central America, Antilles, Colombia, Ecuador, Peru, Brazil, Bolivia; 14 species, 2 in Venezuela, both in the flora area.
Key to the Species of Tynanthus
1. Fruits less than 27 × 1 cm, unwinged; flowers less than 4 mm long; leaves membranous, the lower surface sparsely puberulous; tendrils simple ..... T. polyanthus
1. Fruits > 20 × 2.5 cm, winged; flowers 11-14 mm long; leaves chartaceous, densely white-puberulous on the lower surface; tendrils trifid ..... T. pubescens
Tynanthus polyanthus (Bureau) Sandwith, Kew Bull. 1953: 465. 1954. -Schizopsis polyantha Bureau, Adansonia 5: 378. 1865.
Tynanthus myrianthus Bureau & K. Schum. in Mart., Fl. Bras. 8(2): 197. 1896.
Liana. Moist nonflooded evergreen lowland forests, 100-200 m; Amazonas (scattered). Ecuador, Peru, Amazonian Brazil, Bolivia. Fig. 424.
Tynanthus polyanthus is very distinctive in the tiny, white, strongly bilabiate corolla.
Tynanthus pubescens A.H. Gentry, Mem. New York Bot. Gard. 29: 275. 1978.
Liana. Moist nonflooded evergreen lowland forests, ca. 100 m; Amazonas (south of Puerto Ayacucho). Guyana, Peru, Brazil (Pará).
The only Venezuelan collection, Gentry & Berry 14503 (MO), is sterile and more glabrescent than other material of the species. The type is from Guyana, not far from the Venezuelan border. The conspicuously winged puberulous fruit is very distinctive.
Paul Berry (firstname.lastname@example.org) or Kay Yatskievych (email@example.com).