Mimosa ursina Mart.

Mimosa paucisperma Britton & Rose, sp. nov
Herbaceous, the slender branches terete, brownish, bearing long white hairs. Infrastipular spines in 2's or 3's, yellow; stipules linear, acute, striate, long-ciliate; petioles 7 mm. long or less, long-ciliate; pinnae 1 pair; leaflets 3 or 4 pairs, ovate to short-oblong, 8-10 mm. long, sometimes acutish, glabrous above, but with long-appressed hairs beneath; peduncles 12 mm. long or less, pilose; flowers few, capitate; stamens 5 ; legume oblong, 8-15 mm. long, 2-3-seeded, the margin long-setose, the valves glabrous but with 4—6 porrect prickles at the middle.
Jalisco, Chiapas, September, 1923, Purpus 9306.