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least snoutbean

twining snoutbean

Habit Herbs or subshrubs. Herbs or subshrubs.
Stems

usually prostrate or twining, rarely ascending, rarely viscid, glabrous, puberulent, or villosulous, hairs silvery or grayish, spreading or reflexed.

ascending or erect, tomentulose to hirtellous, hairs silvery to tawny.

Leaves

trifoliolate;

stipules persistent, linear to lanceolate, 1–6 × 1–2 mm, apex acuminate, surfaces puberulent to villosulous;

petiole 4–100 mm, glabrous, tomentulose, or villosulous;

leaflet blades rhombic-orbiculate, rhombic, subrhombic, or ovate, 30–90 × 5–70 mm, membranous or nearly leathery, gland-dotted, base obtuse to rounded, cuneate, or truncate, apex acuminate to obtuse, surfaces glabrous, puberulent, or sparsely to densely villosulous abaxially, glabrous or finely strigose, villosulous, or puberulent adaxially.

usually trifoliolate, proximalmost sometimes unifoliolate;

stipules caducous or persistent, lanceolate to linear-lanceolate, 3–12 × 1.5–3.5 mm, apex acuminate;

petiole 5–35 mm, densely canescent-tomentose abaxially, villous adaxially;

leaflet blades oblong or ovate to rhombic-ovate, elliptic, or obovate, 20–50(–60) × 10–40(–50) mm, leathery, gland-dotted, base obtuse, subcordate, or broadly cuneate, apex acute, obtuse, or rounded, minutely apiculate, surfaces puberulent, strigulose, or villosulous.

Inflorescences

racemes, longer than leaves, 2–20 cm.

racemes, shorter than leaves, axillary ones 1.5–4(–5) cm, terminal ones 6.5–23 cm.

Pedicels

1–5 mm.

1–3 mm.

Flowers

calyx 3–6 mm, puberulent or villosulous, tube 1.5–2 mm, lobes lanceolate, laterals 1.5–4 mm, lengths to 2.5 times tube, adaxials 0.5–1 mm;

corolla yellow, veined purple or brown;

banner orbiculate-ovate, 4–6 × 3–5 mm, emarginate, puberulent, gland-dotted;

wings narrowly oblong, 4.5–5 × 1–2 mm, narrowly gland-dotted, puberulent apically;

keel 5–6 × 2–3 mm, glabrous;

stamens 5–7 mm.

calyx 6–9 mm, hirtellous, tube 1.5–2.5 mm, lobes narrowly lanceolate to linear-subulate, laterals 4.5–7.5 mm, lengths 3+ times tube, adaxials 2–2.5 mm;

corolla yellow or bright yellow;

banner orbiculate, 6–9 × 5–7 mm, emarginate, glabrous;

wings oblong, 6–8 × 1.5–2.5 mm, glabrous;

keel 5–7.5 × 2–2.5 mm, glabrous;

stamens 5.5–7.5 mm.

Legumes

falcate to oblong-ovoid, compressed, 9–20 × 3–5 mm, glabrous, puberulent, or villosulous.

ovoid-oblong, compressed, 15–20 × 5–7 mm, hirtellous and puberulent, hairs intermixed.

Seeds

grayish, brown, black, or mottled, ovoid-reniform, plump, 3–4 × 2–3 mm.

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

2n

= 22.

= 22.

Rhynchosia minima

Rhynchosia tomentosa

Phenology Flowering spring–summer.
Habitat Disturbed areas, forests, edges, prairies, sand dunes.
Elevation 0–100 m. (0–300 ft.)
Distribution
from FNA
AL; AR; FL; LA; MO; MS; TX; Central America; South America; West Indies; Bermuda
[WildflowerSearch map]
[BONAP county map]
from USDA
e United States; s United States
[WildflowerSearch map]
[BONAP county map]
Discussion

Rhynchosia minima was recently collected in Alabama after an absence of over 100 years (A. R. Diamond 2015).

Glycine littoralis Vahl ex de Candolle is an illegitimate name that pertains here.

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

Varieties 2 (2 in the flora).

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

Key
1. Stipules persistent; inflorescences axillary.
var. tomentosa
1. Stipules caducous; inflorescences mostly terminal.
var. mollissima
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. 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. swartzii, R. texana
Subordinate taxa
R. tomentosa var. mollissima, R. tomentosa var. tomentosa
Synonyms Dolichos minimus, Dolicholus minimus, Glycine lamarckii, G. reflexa, Phaseolus caribaeus, R. aureoguttata, R. exigua, R. mexicana, R. minima var. diminifolia, R. minima var. lutea, R. minima var. pauciflora, R. punctata Glycine tomentosa
Name authority (Linnaeus) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle: Prod. 2: 385. (1825) (Linnaeus) Hooker & Arnott: Compan. Bot. Mag. 1: 23. (1835)
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