光梗蒺藜草 guang geng ji li cao

Annual or short-lived perennial. Culms geniculate, decumbent or erect, 40–100 cm tall. Leaf sheaths keeled, loose, glabrous or pilose near margins; leaf blades linear or narrowly lanceolate, 3–20 × 0.2–0.6 cm, glabrous on both surfaces; ligule 0.5–1.5 mm. Inflorescence 1.5–6.5 × ca. 1 cm, open or compact, rachis scabrous. Burrs variable, globose or ovoid, ca. 1 cm, stipe glabrous, spines retrorsely barbed, connate for much of their length, spiny tips diverging irregularly throughout body of burr, involucral cupule cleft on 2 sides, pubescent, spines rigid, long and slender to short and broad. Spikelets 2–3 in burr, 3.5–6 mm; lower glume 1/3–1/2 spikelet length; upper glume 3/4 spikelet length. Fl. and fr. autumn.

Seashore sand dunes. Liaoning [native to America].

This native of America is now widespread as a weed.