Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Genus Description - Spikelets 1-fld, racemose, very shortly pediceled in 2 rows along one side of a rachis, lance-ovoid or ellipsoid; rachilla-joint thickened, forming a ring- like callus below the second glume, the virtually obsolete first glume adnate to it, the spikelet appearing to be set in a thickened, shallow cup atop the pedicel; second glume and sterile lemma chartaceous, 5–7-veined, usually pilose, similar and subequal or the glume a little the longer; fertile lemma surpassed by the second glume, cartilaginous, finely rugulose or papillate-roughened, usually mucronate or awned, the inrolled margins clasping a palea of similar texture and about equal length; tufted grasses with terminal panicles of several, usually appressed racemes. 25, warm reg.