Monographs Details: Glyceria x laxa (Scribn.) Scribn.
Authority: Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Description:Species Description - Much like no. 7 [Glyceria canadensis (Michx.) Trin.], but often taller, with larger (to 4 dm) and very diffuse panicles with smaller spikelets, glumes and lemmas; spikelets ovate, 4–5 mm; 4–6-fld; glumes scarious-margined, the first lanceolate, 1.2–2 mm, the second ovate, 1.8–2.4 mm; lemmas ovate, with visible but not raised veins, 2.3–2.9 mm, the scarious margins almost or quite covering the obovate palea, the obtuse tip scarcely or not at all projecting; male-sterile; 2n=42, 46. Swamps and wet woods; P.E.I. to W.Va. (G. canadensis var. laxa Thought to be a hybrid of no. 7 with no. 10 [Glyceria grandis S. A. Gray] or no. 9 [Glyceria striata (Lam.) Hitchc.]