Kalistroemia brachystylis

Kalistroemia brachystylis Vail, Bull. Torrey Club 24 : 206. 1897.
Tribulus brachystylis B. L. Robinson ; A. Gray, Syn. Fl. N. Am. 1 : 354. 1897.
A profusely branched annual ; stems prostrate, 2-3 dm. long or more, very brittle, swollen at the nodes, sparingly pubescent, with short appressed slightly twisted hairs and fewer longer and spreading cilia; stipules obliquely lanceolate to ovate-lanceolate, 4-5 mm. long, ciliate, at length caducous; petioles shorter than the leaflets; leaves 2-5 cm. long; leaflets 3-4 pairs, obliquely elliptic or oval, 6-15 mm. long, slightly falcate, ciliate on the margin above with somewhat stiff white hairs, paler, hirsute when young, at length glabrous beneath; flowering peduncle 6 mm. long (or longer), in fruit 1.5-2 cm. long, appressed-pubescent ; sepals lanceolate, often caducous before the maturity of the carpels ; petals 4-5 mm. long, orange to pale-yellow, sometimes shorter than the sepals ; fruit minutely pubescent ; beak persistent, glabrous, 1-2 mm. long, obtuse, shorter than the body; nutlets 8-10, about 3 mm. long, with rounded tubercles on the back, strongly reticulate on the faces.
Type locality : Mesa near Las Cruces, New Mexico.
Distribution : From New Mexico to southern Colorado, Arizona, Lower California, and Tamaulipas ; apparently also in Puebla and Oaxaca.