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Texas snoutbean

American snoutbean

Habit Herbs.
Stems

usually prostrate or twining, rarely subascending, puberulent to strigulose or villosulous, hairs silvery.

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

Leaves

trifoliolate;

stipules persistent, linear or linear-lanceolate, 1.5–3 × 0.5 mm, acute to acuminate;

petiole 5–35 mm, puberulous, strigulose, or villosulous;

leaflet blades lanceolate-ovate, 5–45 × 20–25 mm, leathery, gland-dotted, base obtuse or subcordate, margins revolute, apex acute or obtuse, surfaces puberulent, strigulose, or villosulous.

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

1(2 or 3) simple flowers per axil, shorter than leaves, 0.6–1.5 cm.

racemes, shorter than leaves, 1.5–5 cm.

Pedicels

1–6 mm.

2–5 mm.

Flowers

calyx 3–5 mm, villous or villosulous, tube 1.5–2.5 mm, lobes subulate, laterals 1–3.5 mm, lengths to 2.5 times tube, adaxials 0.5–2 mm;

corolla yellow, veined brown;

banner widely ovate, 5–7 × 3.5–5 mm, apex emarginate, puberulent;

wings oblong to ovate, 5–6 × 1–2 mm, glabrous;

keel 5–6.5 × 2–2.5 mm, glabrous;

stamens 4–6 mm.

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, compressed, 15–25 × 4–6 mm, puberulent-hirtellous, hairs intermixed.

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

Seeds

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

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

Vines

, herbaceous.

2n

= 22.

= 22.

Rhynchosia texana

Rhynchosia americana

Phenology Flowering spring–summer. Flowering spring–summer.
Habitat Dry limestone, sandy or igneous soils, grasslands, canyons, mountain slopes, roadsides, forest clearings. Sandy soils, prairies, fields, oak woodlands, roadsides, sand dunes.
Elevation 40–2700 m. (100–8900 ft.) 0–300 m. (0–1000 ft.)
Distribution
from FNA
AZ; NM; TX; South America; Mexico (Chiapas, Chihuahua, Coahuila, Durango, Nuevo León, Puebla, San Luis Potosí, Sonora, Tamaulipas, Veracruz)
from FNA
TX; Mexico (Chiapas, Durango, San Luis Potosí, Sinaloa, Tamaulipas, Veracruz)
[BONAP county map]
Discussion

Rhynchosia angustifolia Engelmann ex A. Gray is an illegitimate name that pertains here. Dolicholus texensis Vail and its var. angustifolius (A. Gray) Vail are illegitimate and superfluous names that also pertain here.

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

In Texas, Rhynchosia americana occurs in coastal and southern 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. americana, R. cinerea, R. cytisoides, R. difformis, R. edulis, R. latifolia, R. michauxii, R. minima, R. parvifolia, R. precatoria, R. reniformis, R. swartzii, R. tomentosa
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 R. senna var. angustifolia, R. senna var. cordobensis, R. senna var. texana, R. texana var. angustifolia, R. texana var. microphylla Lathyrus americanus, Glycine menispermoides, Phaseolus menispermoideus, R. menispermoidea
Name authority Torrey & A. Gray: Fl. N. Amer. 1: 687. (1840) (Miller) Metz: Catholic Univ. Amer., Biol. Ser. 16: 126. (1934)
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