Herbs, perennial. Stems erect, 50–200 cm, medially uncinate-­pubescent and patent-villous. Leaves trifoliolate; stipules per­sistent, often patent or reflexed, obliquely ovate and apex acuminate or narrowly ovate and apex aristate, 3–12.5 mm, base amplexicaul; petiole 8–50 mm; leaflet blades narrowly ovate to ovate, elliptic, or rhombic, apex obtuse or acute, surfaces obscurely prominently reticulate-veined abaxially, uncinate-puberulent and strigose or subappressed-villous; ter­minal blade (20–)40–150 × 10–50 mm, length 2–3 times width. Inflorescences branched or unbranched; rachis villous (often with bulbous hairs) and uncinate-puberulent, or only uncinate-puberulent; primary bracts caducous, narrowly ovate, 4 mm. Pedicels 10–15 mm. Flowers: calyx 1.5–3 mm, uncinate-puberulent, tube to 1 mm; abaxial lobes 2 mm, lateral lobes 1 mm; corolla lavender, 4–6 mm. Loments: margins alternately involute and revolute, sutures equally crenate, twisted conspicuously when young; connections central, 1/4 as broad as segments; segments (3 or)4–7, orbiculate, broadly elliptic, or rhombic, 3–4.5 × 3–3.5 mm, rounded abaxially and adaxially, densely uncinate-pubescent; stipe 0.5–1 mm. 2n = 22.

Phenology: Flowering summer–fall (year-round).
Habitat: Open, dis­turbed sites, ruderal areas, pinelands, savannas.
Elevation: 0–300 m.

Distribution

• Generated Map
• Legacy Map

Introduced; Ala., Ark., Fla., Ga., La., Miss., N.C., S.C., Tex., Mexico (Chiapas, Colima, Guerrero, Jalisco, Nayarit, Oaxaca, Sinaloa, Sonora), West Indies, Central America, South America, introduced also in Asia, Africa, Indian Ocean Islands, Pacific Islands, Australia.

Discussion

Desmodium tortuosum is most easily distinguished from its relatives by the thick leaflets with prominent reticulate venation, the large persistent stipules, and the long, stiff, ascending to spreading pedicels (B. G. Schubert 1980).

Selected References

None.

Lower Taxa

None.