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least snoutbean

Chihuahuan snoutbean

Habit Herbs or subshrubs. Herbs.
Stems

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

erect, suberect, decumbent, procumbent, or twining, viscid, hirsute, hairs yellowish.

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.

trifoliolate;

stipules persistent, linear to narrowly lanceolate, 3–9 × 0.5–1.5 mm, apex acute to acuminate, surfaces hirsute;

petiole 15–55 mm, hirsute;

leaflet blades lanceolate to obovate-oblong or ovate-deltate, 15–70 × 10–60 mm, membranous or leathery, gland-dotted, often viscid, base obtuse to rounded or truncate, margins ciliate, slightly revolute, apex acute to acuminate, surfaces strongly reticulate and sparsely to densely hirsute abaxially, strigulose to strigose adaxially.

Inflorescences

racemes, longer than leaves, 2–20 cm.

racemes, equal to or longer than leaves, 2.5–20 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 4–7 mm, hirsute, tube 1.5–2 mm, lobes lanceolate, laterals 2–2.5 mm, lengths to 2.5 times tube, adaxials 1.5–3 mm;

corolla yellow, striped reddish brown or purple;

banner widely ovate to obovate, 7–10 × 4–5 mm, slightly apiculate, hirtellous and gland-dotted;

wings narrowly oblong, 6.5–9 × 1.5–2 mm, gland-dotted, puberulent apically;

keel 6.5–9 × 2–3 mm, glabrous;

stamens 6–9 mm.

Legumes

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

oblong-ovoid, compressed, 16–26 × 6–8 mm, often viscid, long-hirsute to puberulent, hairs intermixed, glabrescent.

Seeds

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

greenish brown or mottled, widely ovoid to subglobose, compressed, 4–5 × 3–4 mm.

2n

= 22.

Rhynchosia minima

Rhynchosia edulis

Phenology Flowering spring–summer. Flowering spring–summer.
Habitat Disturbed areas, forests, edges, prairies, sand dunes. Sandy or clay soils of woodland, thickets, ravines, pastures, stream banks, roadsides.
Elevation 0–100 m. (0–300 ft.) 800–1500 m. (2600–4900 ft.)
Distribution
from FNA
AL; AR; FL; LA; MO; MS; TX; Central America; South America; West Indies; Bermuda
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; Central America; South America; Mexico (Chiapas, Durango, Guerrero, Jalisco, Michoacán, Nayarit, San Luis Potosí, Sonora, Veracruz)
[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.)

In Arizona, Rhynchosia edulis is found only in Santa Cruz County.

Dolicholus melanostictus (Grisebach) Kuntze is an illegitimate name that pertains here.

(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. parvifolia, R. precatoria, R. reniformis, R. swartzii, R. texana, R. tomentosa
R. americana, R. cinerea, R. cytisoides, R. difformis, R. latifolia, R. michauxii, R. minima, R. parvifolia, R. precatoria, R. reniformis, R. swartzii, R. texana, R. 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 Dolicholus apoloensis, D. ixodes, Eriosema edule, E. nigropunctatum, E. volubile, R. apoloensis, R. ixodes, R. melanosticta, R. nigropunctata, R. pinetorum, R. rariflora, R. rupicola
Name authority (Linnaeus) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle: Prod. 2: 385. (1825) Grisebach: Abh. Königl. Ges. Wiss. Göttingen 19: 123. (1874)
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