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American snoutbean

Stems

procumbent, trailing, or twining, villous or villosulous, hairs silvery, spreading.

Leaves

usually unifoliolate, distalmost rarely trifoliolate;

stipules persistent, ovate-lanceolate, 2–5 × 1–2.5 mm, apex acuminate;

petiole 10–45 mm, villosulous;

leaflet blades suborbiculate to reniform, 15–40 × 20–55 mm, leathery, gland-dotted, base cordate, apex broadly rounded, surfaces villosulous abaxially, rugose and finely strigose adaxially.

Inflorescences

racemes, shorter than leaves, 1.5–5 cm.

Pedicels

2–5 mm.

Flowers

calyx 7–13 mm, villosulous, tube 1.5–2 mm, lobes lanceolate, laterals 6–10 mm, adaxials 2–4 mm;

corolla yellow, often tinged brown;

banner obovate, 8.5–10 × 6.5–7.5 mm, emarginate, puberulous;

wings narrowly oblong, 6.5–7.7 × 2–2.5 mm, glabrous;

keel 8–9 × 3–3.5 mm, glabrous;

stamens 7.5–8.5 mm.

Legumes

oblong-ovoid, compressed, 10–15 × 5–8 mm, villosulous.

Seeds

brown, black, or mottled, subglobose, compressed, 3–4 × 3–3.5 mm.

Vines

, herbaceous.

2n

= 22.

Rhynchosia americana

Phenology Flowering spring–summer.
Habitat Sandy soils, prairies, fields, oak woodlands, roadsides, sand dunes.
Elevation 0–300 m. (0–1000 ft.)
Distribution
from FNA
TX; Mexico (Chiapas, Durango, San Luis Potosí, Sinaloa, Tamaulipas, Veracruz)
[BONAP county map]
Discussion

In Texas, Rhynchosia americana occurs in coastal and southern counties.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Rhynchosia
Sibling taxa
R. cinerea, R. cytisoides, R. difformis, R. edulis, R. latifolia, R. michauxii, R. minima, R. parvifolia, R. precatoria, R. reniformis, R. swartzii, R. texana, R. tomentosa
Synonyms Lathyrus americanus, Glycine menispermoides, Phaseolus menispermoideus, R. menispermoidea
Name authority (Miller) Metz: Catholic Univ. Amer., Biol. Ser. 16: 126. (1934)
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