Rhizomes elongate, covered with shiny, coriaceous, scalelike leaves.Culms to 2.4 m. Sheaths glabrous or sparsely to densely pubescent;ligules 0.7-2.5 mm; blades to 64 cm long, about 12 mm wide. Panicles 15-78 cm long, 1.7-26.4 cm wide; branches to 33 cm, erect to strongly divergent, lowermost branches sometimes reflexed. Spikelets 5-8.5 mm. Glumes straight; lower glumes 3.5-6.5 mm; upper glumes 5-8.2 mm; lemmas 4.5-7.1 mm, straight, glabrous; paleas 4.4-6.9 mm, glabrous. 2n = 40, ca. 60.
Calamovilfa longifolia usually grows in sand or sandy soils, but is occasionally found in clay soils or loess. Two geographically contiguous varieties exist. They differ as shown in the following key; the differences between the two are more striking in the field.
Vascular Plants of NE US and adjacent Canada
Stout, to 2 m, from long rhizomes; sheaths to 15 cm; ligule 1-1.5 mm; blades to 60 cm נ12 mm, not articulated to the sheath; infl 1.5-7 dm; first glume 3.5-6.5 mm, the second 5-8 mm; lemma 4.5-7 mm, glabrous except for the callus-hairs half to seven-eighths as long; palea glabrous; 2n=40, 60. Two well marked vars.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.