Herbs, subshrubs, or shrubs, perennial; stoloniferous or rhizomatous. Stems erect or ascending, to 300 cm, pubescent or glabrescent. Leaves trifoliolate; stipules usually persistent, narrowly ovate-deltate, 5–10 mm; petiole usually 15–20 mm; leaflet blades elliptic to ovate, apex obtuse or acute, surfaces finely spreading-villosulous to substrigose abaxially, uncinate-puberulent or glabrescent adaxially; terminal blade 20–90 × 15–45 mm, length 1.5–4 times width. Inflorescences unbranched; rachis densely patent uncinate-pubescent; primary bracts caducous, narrowly ovate, 6–7 mm. Pedicels persistent with calyx-remnant at top after loments drop, 5–9 mm. Flowers: calyx 2–3.5 mm, uncinate-puberulent, lobes pilose, tube 1 mm; abaxial lobes 1.5–2.5 mm, lateral lobes 1–2 mm; corolla purple, 5–8 mm. Loments: sutures symmetrically crenate abaxially, straight or slightly sinuate adaxially; connections central, 1/2–2/3 as broad as segments; segments 4–8, semiobovate, 3.5–5 × 2.5–3 mm, broadly rounded abaxially, straight or barely convex adaxially, uncinate-puberulent; stipe 1.5–2 mm. 2n = 22.

Phenology: Flowering spring–fall.
Habitat: Pine-palmetto flatwoods, woodland borders, lawns, ruderal sites, disturbed or waste areas.
Elevation: 0–50 m.

Distribution

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Introduced; Ala., Fla., Ga., Tex., Mexico (Chiapas, Jalisco, Oaxaca, Quintana Roo, Tamaulipas, Veracruz), West Indies, Central America, South America, introduced also in Asia (Taiwan), Africa, Indian Ocean Islands (Mauritius, Reunion), Pacific Islands, Australia.

Discussion

Desmodium incanum may be distinguished by its long-persistent stipules usually fused and nearly surrounding the stem, at least when young, and by its pedicels which are usually borne singly and are each subtended by one primary bract and two (lateral) secondary bracts (B. G. Schubert 1980).

Desmodium incanum was long known as D. canum Schinz & Thellung (= Meibomia cana S. F. Blake) based on the illegitimate Hedysarum canum J. F. Gmelin, a superfluous name for H. racemosum Aublet. The complex nomenclatural history was elaborated by D. H. Nicolson (1978) and L. C. P. Lima et al. (2012, 2014). Hedysarum canescens Miller (1768) is a later homonym of H. canescens Linnaeus (1753), thus illegitimate, and pertains here. Hedysarum canum J. F. Gmelin is a superfluous name for H. racemosum Aublet; Meibomia cana S. F. Blake was intended as a new combination based on that name.

Selected References

None.

Lower Taxa

None.