Panicum philadelphicum Trin.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Slender annual 1–5 dm, erect or rarely decumbent, branched from the base; blades usually yellowish-green, 3–8 mm, wide; pedicel well exsert; panicle ovoid, ca a third as long as the entire plant; spikelets tending to be paired at the ends of capillary branches; axillary pulvini short-villous to glabrous; spikelets ovoid to ellipsoid, 1.6–2.4 mm, the first glume obtuse or acute, two-fifths as long as the abruptly acuminate second glume and sterile lemma; fr plump, becoming blackish; margins of the lemma barely inrolled, the exposed part of the palea half to three-quarters as wide as the fr; 2n=18. Dry soil and sand fields; N.S. and N.Y. to Minn., s. to Ga. and Tex. (P. tuckermanii, the form, chiefly northern, with the axillary pulvini glabrous)