Culms clustered, stiff, erect or ascending, 1-6 dm, usually at least some of the sheaths and internodes with distinctly bistratal pubescence consisting of intermingled short, soft, crisp hairs and much longer (1-2+ mm) coarser hairs; sheaths conspicuously striate; ligule a dense band of short (ca 1 mm or less) hairs in front of a thin line of longer (even to 5 mm) hairs; blades ascending, 4-9 cm נ3-7 mm, involute at the tip, glabrous or with a few scattered long hairs above, glabrous to more often hairy (with unequal hairs) beneath; primary panicle ovoid, 3-8 cm; spikelets finely hairy, ellipsoid, 1.7-2.6 mm; autumnal phase becoming widely spreading to prostrate, branched chiefly from the middle nodes, the blades scarcely reduced, the panicles much reduced and surpassed by the lvs; 2n=18. Sandy soil. Var. commonsianum, of the coastal plain from Mass. to Fla., is rather thinly hairy. (P. addisonii; P. mundum) The more copiously hairy var. euchlamydeum (Shinners) Pohl is more inland, occurring from nw. Pa. to n. Ill., Wis., and e. Minn. P. commonsianum might perhaps properly be subordinated to P. ovale Elliott, of the southern coastal plain, but the proper nomenclatural innovations have not been made.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.