The Manual of the Botany of the Northern United States / Including the District East of the Mississippi and North of North Carolina and Tennessee

by Asa Gray

32. Apera. Flowering glume bifid, awned. Panicle very loose and delicate.

33. Calamagrostis. Flowers hairy-tufted at base. Glumes membranaceous. Palet thin.

34. Ammophila. Spikelets large. Flowers hairy tufted at base. Glumes and palet chartaceous.

Tribe VII. AVENEÆ. Spikelets 2–several-flowered, panicled, the rhachis or base of the flowers often bearded; upper flower imperfect or rudimentary (except in n. 37). Flowering glume bearing a twisted, bent or straight awn on its back or below the apex.

[*] One of the flowers staminate only.

35. Arrhenatherum. Lower flower staminate, long awned; middle flower perfect, nearly awnless; the upper rudimentary.

36. Holcus. Flowers 2, the lower perfect, awnless, the upper staminate, awned.

[*][*] Flowers all perfect or the uppermost usually rudimentary.

37. Aira. Spikelets very small, in a diffuse panicle. Flowers 2, perfect, awned toward the base.

38. Deschampsia. Spikelets 2-flowered, with a hairy rudiment. Glumes thin-scarious, the flowering one erose-truncate awned near the middle.