Bulb Panicgrass

Panicum bulbosum H. B. K. Nov. Gen. & Sp. 1: 99. 1815
Panicum avenaceum H. B. K. Nov. Gen. & Sp. 1: 99. 1815. Panicum gongylodes Jacq. f. Bclog. Gram. 30. 1815. Panicum confusum Trin.; Nees, Agrost. Bras. 174, as synonym. 1829. Panicum nodosum Willd.; Steud. Nom. ed. 2. 2: 260, as synonym. 1841. Panicum maximum gongylodes Doell, in Mart. Fl. Bras. 2 2 : 203. 1877. Panicum maximum bulbosum Vasey, in Rothr. Bot. Wheeler's Surv. 295. 1878. Panicum polygamum gongylodes Fourn. Mex. PL Gram. 28. 1886. Panicum bulbosum avenaceum Beal, Grasses N. Am. 2: 132. 1896.
Plants in tufts of few to several culms, 1-2 meters high ; culms robust, erect, glabrous, the lowest internode thickened into a hard, corm-like base, 1-2 cm. thick, budding at the base, sometimes one or more corms of previous years attached; leaf-sheaths shorter than the internodes, glabrous or scabrous to pilose toward the summit, the lower often appressed-pubescent at base; ligule scarcely 1 mm. long; blades erect or ascending, flat, 25-60 cm. long, 3-12 mm. wide, scabrous on the upper surface, often pilose toward the base, glabrous beneath; panicles long-exserted, 20-50 cm. long, usually about half as wide, rather many-flowered, the slender, flexuous branches ascending or somewhat spreading, solitary or fascicled, naked at the base, the branchlets 1 to several cm. long, bearing scarcely clustered, rather short-pediceled spikelets, the axes and pedicels very scabrous; spikelets 3.5-4.2 mm. long, 1.2-1.4 mm. wide, slightly pointed, more strongly nerved than in P. maximum, glabrous, commonly purplish; first glume half to two thirds the length of the spikelet, bluntly pointed, 3-nerved; second glume shorter than the fruit and sterile lemma, the latter rarely inclosing a staminate flower; fruit 3.2-4 mm. long, narrowly ovate, more finely transversely rugose than in P. maximum, the bluntly pointed apex puberulent.
Type locality: Near Guanajuato, Guanajuato. Distribution: New Mexico to Arizona and southern Mexico.