Herbs, perennial. Stems ascend­ing to erect, usually striate, branched or unbranched, 30–150 cm, glabrous or sparsely to densely uncinate-puberulent, sometimes also patent long-pilose. Leaves trifoliolate; stipules caducous or moderately persistent, subulate to narrowly ovate, 2–5 mm; petiole 1–30 mm; leaflet blades narrowly ovate, elliptic, elliptic-ovate, ovate-rhombic, or suborbiculate, apex obtuse or acute, mucronulate, surfaces sparsely to densely uncinate-puberulent and appressed-villous abaxially, uncinate-puberulent or glabrescent adaxially; terminal blade 9–75 × 6–33 mm, length 1.5–4(–5) times width. Inflorescences terminal and branched, axillary and unbranched; rachis uncinate-puberulent; primary bracts ovate, 1.5–3 mm. Pedicels 3–19 mm, uncinate-puberulent. Flowers: calyx 1.5–2.5 mm, pubescent (not uncinate-puberulent), tube 1 mm; abaxial lobes 1.2–1.5 mm, lateral lobes 1 mm; corolla usually lavender to red-violet or pink-purple, rarely white, 4–6 mm. Loments: sutures crenate abaxially, sinuate adaxially; connections adaxial, 1/4–1/2 as broad as segments; segments 1–4, broadly elliptic, 3.5–5.5 × 2.5–4 mm, rounded abaxially, convex adax­ially, uncinate-puberulent throughout; stipe 1–2 mm. 2n = 22.

Distribution

e, sc United States, West Indies.

Discussion

Varieties 3 (3 in the flora).

Desmodium ciliare, D. lancifolium, and D. marilandicum have generally been recognized as closely related but distinct species in floras of the United States. They commonly have two or three articulate, small loments. D. Isely (1990, 1998) grouped them as the D. ciliare Group and regarded forms intermediate between them as putative hybrids: D. ciliare × D. marilandicum and D. ciliare × D. lancifolium. They have been separated by differences in the leaflets and pubescence, but the differences are not always clear. They are treated here as one species with three varieties.

Selected References

None.

Lower Taxa

Desmodium marilandicum var. ciliare, Desmodium marilandicum var. lancifolium, Desmodium marilandicum var. marilandicum

Key

1	Terminal leaflet blades elliptic-ovate to narrowly ovate, 50–75 × 20–33 mm, apex acute to obtuse.	Desmodium marilandicum var. lancifolium
1	Terminal leaflet blades elliptic, ovate, ovate-rhombic, or suborbiculate, 9–40 × 6–17 mm, apex obtuse.	> 2
2	Petioles 12–30 mm, sparsely uncinate-puberulent; stems with a few, scattered hairs; pedicels (6–)8–19 mm.	Desmodium marilandicum var. marilandicum
2	Petioles 1–15 mm; stems and petioles uncinate-puberulent and patent long-pilose; pedicels.	Desmodium marilandicum var. ciliare