Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Stems erect to prostrate annual, herbs or small shrubs 10-50 cm tall. Leaves: Trifoliate leaves, leaflets linear to linear-lanceolate, not more than 5 mm wide, to 4 cm long, bright green with reticulate veins, sparsely pilose to subglabrate above, paler to pubescent beneath. Flowers: In terminal or axillary racemes, simple or compound, corolla purplish 3-3.5 mm long. Fruits: Flat loments with 1-4 single seeded segments, segments less than 5 mm long, orbicular to elliptic, indehiscent, glabrous, margins flat, not contorted or nearly so. Ecology: Found on slopes, mesas, and grasslands, from 3,500-6,500 ft (1067-1981 m); flowering August-September. Notes: Look to the glabrous, orbicular to elliptic loments with flat margins to help identify this species. These plants can be vining, and the leaves can appear as three linear, palmate leaflets. Ethnobotany: There is no specific use recorded for this species, however the genus was used as an infusion to treat vomiting and colds and as a wash for sores. Etymology: Desmodium is from the Greek desmos for chain, which is a reference to the jointed seed pods, while rosei is named for Lewis Samuel Rose (1893-1973) an American botanical collector. Synonyms: None Editor: LCrumbacher, 2011
Annual, Herbs, Taproot present, Nodules present, Stems erect or ascending, Stems or branches arching, spreading or decumbent, Stems less than 1 m tall, Stems solid, Stems or young twigs sparsely to densely hairy, Stems with hooked uncinate hairs or prickles, Leaves alternate, Leaves petiolate, Stipules conspicuous, Stipules green, triangulate to lanceolate or foliaceous, Stipules setiform, subulate or acicular, Stipules deciduous, Stipules free, Leaves compound, Leaves pinnately 3-foliolate, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Stipels present at base of leaflets, Leaflets 3, Leaves hairy on one or both surfaces, 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, Petals blue, lavander to purple, or violet, 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 stipitate, Fruit unilocular, Fruit indehiscent, Fruit elongate, straight, Fruit exserted from calyx, Fruit compressed between seeds, Fruit glabrous or glabrate, Fruit 2-seeded, Fruit 3-10 seeded, Seeds ovoid to rounded in outline, Seeds reniform, Seed surface smooth, Seeds olive, brown, or black.