Sorghum halepense (L.) Pers.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Robust perennial to 1.5 m, colonial by long rhizomes; lvs elongate, 1–2 cm wide; panicle 1.5–4 dm, open, its main axis glabrous or scabrous; sessile spikelet silky, 4–6 mm, the pediceled one staminate (or neuter), glabrous, slightly longer; awn 1–1.5 cm; 2n=40. Native to the Mediterranean region, cult. for forage, escaped and well established as a weed especially in the s. part of our range, but also n. to Mass. and Mich. (Holcus h.; S. miliaceum) Under some conditions the plant becomes poisonous through the production of prussic acid. Johnson-grass is the result of hybridization with cult. sorghum.