Digitaria ischaemum (Schreb.) Muhl.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Plants forming loose tufts, ascending or suberect, only seldom rooting at the lower nodes; herbage glabrous (or the upper margins of the sheaths ciliate); racemes 2–5(–8), 4–10(–15) cm; spikelets elliptic or somewhat obovate, 1.7–2.3 mm; becoming dark brown or purple-black; first glume lacking or minute and hyaline; second glume and sterile lemma equal and as long as the spikelet, both ± pubescent or subtomentose with capitellate hairs, especially in strips between the veins; 2n=36, 45; otherwise much like no. 4 [Digitaria sanguinalis (L.) Scop.]. Native of Eurasia, now established as a weed over much of the U.S., and throughout our range, but less abundant than no. 4. (D. humifusa)