Rhynchosia senna var. texana is a prostrate and spreading herb with dark green leaflets which have impressed veins and are ciliate edged. The flowers are solitary or in pairs in leaf axils. Rhynchosia senna var. texana is found in dry ground at middle elevation.
Wiggins 1964, Kearney and Peebles 1969
Duration: Perennial Nativity: Native Lifeform: Vine General: A slender, twining or scrambling vine with stems 1-20 dm long from a woody root, minutely puberulent throughout, stipules lance-setaceous, 2-2.5 mm long. Leaves: Petioles slender, 5-12 mm long, petiolule of terminal leaflet from half as long as to equaling petiole; leaflets narrowly ovate-lanceolate to lanceolate, 3-10 mm wide, 1-5 cm long, rounded at base, acute and muctonulate at apex. Flowers: Solitary to few flowered clusters in axils, pedicels 4-5 mm long, calyx tube 1.5 mm long, finely villous with short spreading hairs, teeth linear-subulate, 1.5-2.5 mm long, corolla yellow, 5-6 mm long. Fruits: Pods lunate, 5-7 mm wide, about 2 cm long, finely and closely puberulent, minute beak turned abruptly downward. Ecology: Found on the margins of grassy plains, among shrubs, and on mesas from 3,500-5,500 ft (1067-1676 m); flowers May-September. Distribution: AZ, NM, TX; south to s MEX, and in S. Amer. Notes: Distinguished by being a trailing, but low-growing vine with trifoliate leaves, the dark-green leaflets with punctate (sunk-in) glands, and veins obvious on the bottom surfaces; small, bright yellow flowers; and strongly compressed pods. Specimens in southern Arizona have hairs on the stem that are appressed or subppressed and retrorse, while those further north have spreading or ascending hair. Ethnobotany: Unknown Etymology: Rhynchosia is from Greek rhynchos, horn, beak or snout, while senna from the Arabic name sana. Synonyms: Rhynchosia texana Editor: SBuckley 2010, FSCoburn 2015