Scandent, suffruticose plants, the branchlets subterete but angled or ridged, glabrous or somewhat pubescent, densely armed with recurved, broad-based thorns. Leaves moderately large, bipinnate, the pinnae 1 pair, the leaflets mostly 3-4 pairs; petiole elongate, as much as 10 cm. long, eglandular, callous basally, apiculate terminally, armed like the twigs; pinnae 3-7 cm. long, the rachis pulvinate and usually aculeate; leaflets inequilaterally elliptic to oblong-lanceolate, mostly 10-30 mm. long and 5-15 mm. wide, acute apically, obliquely rounded basally, callous basally and with a few conspicuous palmate veins, setose-ciliate on the margins, sometimes with a few appressed setae on the lower surface; stipules narrowly linear-lanceolate, falcate, commonly about 5 mm. long, striate. Inflorescence of axillary, pedunculate heads; peduncles short, 5-15 mm. long; heads globular, several-to many-flowered, the floral bractlets linear-lanceolate, 1-2 mm. long. Flowers small, sessile, dense, whitish; calyx very minute; corolla funnelform, 1-2 mm. long, glabrous, 4-lobed, the lobes half as long as the tube; stamens 4, about 1 cm. long, free, glabrous; ovary short, setose, bilateral, the style slightly exceeding the stamens. Legume oblong, usually 30-40 mm. long and about 12 mm. wide, flat, glabrous, 4-to 5-segmented, the margins setose-spinose and persistent.
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