Annual to short-lived perennial, slender, 3-10 dm; sheaths glabrous or sparsely villous at the summit; blades 2-18 cm נ2-6 mm; bur 5.5-10 נ2.5-5 mm (spines excluded), usually rather shortly hairy, cleft on 2 sides, with mostly 8-40 basally flattened, retrorsely barbed spines 2-5 mm; spikelets 3.5-6 mm, 2-4 per bur, exserted at the tip; 2n=34. Sandy soil; trop Amer., n. to se. Va., Ark., and Kans.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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