A series of largely sterile hybrids between spp. 1 and 4; spikelets in the size range of no. 1 [Sphenopholis obtusata (Michx.) Scribn.], but the first lemma with an awn to 3.5 mm.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.