Desmodium procumbens (P. Mill.) A.S. Hitchc.
Family: Fabaceae
Western Trailing Tick-Trefoil,  more...
[Hedysarum procumbens ]
Desmodium procumbens image
Wiggins 1964, Kearney and Peebles 1969

Duration: Annual

Nativity: Native

Lifeform: Forb/Herb

General: Erect or ascending annual 10-60 cm tall, sparsely to densely uncinate-hispidulous stems and branches.

Leaves: On petioles 1-5 cm long, puberulent to subglabrate, with stipules narrowly ovate acuminate or attenuate, 1-4.5 mm long, ciliate along margins, basal leaves unifoliolate, leaflet broadly rhombic to transversely elliptic, entire or faintly 3-lobate, 5-15 mm wide, 1-7 cm long, upper leaves more linear to linear-lanceolate 3-12 mm wide, 1-6 cm long, glabrous, gray-green.

Flowers: In terminal and axillary racemes with a small corolla, branches to 20 cm long, calyx 1.5-2 mm long, with minute short-ciliate teeth; corolla yellowish or greenish, 3-4 mm long.

Fruits: Spirally twisted loment, uncinate-puberulent, 3-6 jointed, joints 1.5-3 mm wide, 2.5-4.2 mm long, margins alternately involute and revolute, appearing spirally twisted.

Ecology: Found on slopes, in canyons and on grassy flats from 3,500-6,500 ft (1067-1981 m); flowers August-September.

Notes: It is difficult to distinguish among the Desmodium so consulting a key to clearly discern is useful. This description is a merging of the old description for var. procumbens and var. exiguum, which appear to have been merged in recent years.

Ethnobotany: Unknown

Etymology: Desmodium might come from the Greek desmos meaning bond, fastening or chain, referring to the loment, while procumbens means having trailing or prostrate stems.

Synonyms: None

Editor: SBuckley, 2010

Perennial, Herbs, Stems woody below, or from woody crown or caudex, Taproot present, Nodules present, Stems prostrate, trailing, or mat forming, Stems less than 1 m tall, Stems 1-2 m tall, Stems solid, Stems or young twigs sparsely to densely hai ry, Stems with hooked uncinate hairs or prickles, Leaves alternate, Leaves petiolate, Stipules conspicuous, Stipules green, triangulate to lanceolate or foliaceous, Stipules free, Stipules cordate, lobed, or sagittate, Leaves simple, or appearing so, Leaves compound, Leaves pinnately 3-foliolate, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Stipels present at base of leaflets, Leaflets 1, Leaflets 3, Leaves glabrous or nearly so, Inflorescences racemes, Inflorescence panicles, Inflorescence axillary, Inflorescence terminal, Bracts very small, absent or caducous, Bracteoles present, Flowers zygomorphic, Calyx 2-lipped or 2-lobed, Calyx hairy, Petals separate, Corolla papilionaceous, Petals clawed, Petals pinkish to rose, Banner petal ovoid or obovate, Wing petals narrow, oblanceolate to oblong, Wing tips obtuse or rounded, Keel tips obtuse or rounded, not beaked, Stamens 9-10, Stamens diadelphous, 9 united, 1 free, Filaments glabrous, Style terete, Fruit a loment, jointed, separating into articles, Fruit unilocular, Fruit indehiscent, Fruit elongate, straight, Fruit exserted from calyx, Fruit compressed between seeds, Fruit hairy, Fruit 3-10 seeded, Seeds ovoid to rounded in outline, Seeds reniform, Seed surface smooth, Seeds olive, brown, or black.