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American snoutbean

swartz's snoutbean

Habit Herbs or subshrubs.
Stems

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

trailing or twining, gland-dotted, soft-hirsute, hairs silvery.

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.

trifoliolate;

stipules persistent, narrowly lanceolate to lanceolate, 3–4 × 0.5–1.5 mm, acuminate, surfaces hirtellous;

petiole 10–60 mm, hirsute;

leaflet blades ovate, 20–60 × 15–45 mm, membranous, gland-dotted abaxially, base obtuse, rounded, or truncate, apex acute or long-acuminate, surfaces hirsute abaxially, glabrous or hirsute adaxially.

Inflorescences

racemes, shorter than leaves, 1.5–5 cm.

racemes, longer than leaves, 1–6 cm.

Pedicels

2–5 mm.

filiform, 2–4 mm, viscid.

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.

calyx 3.5–5 mm, hirsute-viscid, tube 2.5–5 mm, lobes broadly lanceolate, laterals 1.5–2 mm, lengths to 2.5 times tube, adaxials 0.5–1 mm;

corolla yellow;

banner obovate, 5–8 × 3–4.5 mm, marginate, puberulent, gland-dotted;

wings oblong, 4–5 × 1–1.5 mm, glabrous;

keel 4.5–5 × 2-2.5 mm, glabrous;

stamens 3.5–5 mm.

Legumes

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

brown, acinaciform, compressed, 25–40 × 5–9 mm, tapered toward base, densely puberulent, hairs long, scattered.

Seeds

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

brown to red, reniform, barely compressed, 4–6 × 3–3.5 mm.

Vines

, herbaceous.

2n

= 22.

Rhynchosia americana

Rhynchosia swartzii

Phenology Flowering spring–summer. Flowering spring.
Habitat Sandy soils, prairies, fields, oak woodlands, roadsides, sand dunes. Sandy soils, hammocks, thickets, open woods, pastures, roadsides.
Elevation 0–300 m. (0–1000 ft.) 0–10 m. (0–0 ft.)
Distribution
from FNA
TX; Mexico (Chiapas, Durango, San Luis Potosí, Sinaloa, Tamaulipas, Veracruz)
[BONAP county map]
from FNA
FL; s Mexico; West Indies (Bahamas, Greater Antilles)
[BONAP county map]
Discussion

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

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

In the flora area, Rhynchosia swartzii is found in Miami-Dade and Monroe counties.

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

Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Rhynchosia 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
R. americana, R. cinerea, R. cytisoides, R. difformis, R. edulis, R. latifolia, R. michauxii, R. minima, R. parvifolia, R. precatoria, R. reniformis, R. texana, R. tomentosa
Synonyms Lathyrus americanus, Glycine menispermoides, Phaseolus menispermoideus, R. menispermoidea Dolicholus swartzii, R. gundlachii
Name authority (Miller) Metz: Catholic Univ. Amer., Biol. Ser. 16: 126. (1934) (Vail) Urban: Repert. Spec. Nov. Regni Veg. 15: 320. (1918)
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