Description from Flora of China
Campeiostachys Drobow; Clinelymus (Grisebach) Nevski, nom. superfl.; Elymus sect. Clinelymus Grisebach; Goulardia Husnot; Roegneria K. Koch; Semeiostachys Drobow; Terrellia Lunell, nom. illeg. superfl.
Plants perennial, usually tufted, usually without, rarely with, rhizomes. Culms usually erect. Leaf sheath of cauline leaves split almost to base; auricles present or absent; leaf blade flat or rolled. Spike erect to nodding. Spikelets 1 or 2(–4) per node, sessile, rarely very shortly pedicellate, appressed to rachis, clearly laterally compressed, usually all similar, with 2–10 or more florets; rachis tough. Glumes opposite or side-by-side, linear-lanceolate to lanceolate-ovate, firmly membranous to leathery, 1–9(–11)-veined, not keeled, apex obtuse to shortly awned; veins ± raised. Lemma lanceolate-oblong, rounded abaxially, 5-veined, ± pubescent, apex obtuse or acute to awned, rarely toothed; veins connivent at apex; awn erect or reflexed. Palea shorter than or equaling lemma, apex retuse, subrounded, or acute. Caryopsis usually adherent to lemma and palea. x = 7.
The genus Roegneria should be referred to Elymus because of their many common characters, e.g., plants usually tufted; spikelets usually all similar, 1 per node; lemma lanceolate-oblong, rounded abaxially, 5-veined, veins connivent at apex.
The name Roegneria aduoensis S. L. Lu & Y. H. Wu (Guihaia 28(3): 285. 2008) appeared after publication of the family treatment for the Flora of China.
In addition, two North American species have been recorded as cultivated in China (FRPS 9(3): 10, 66. 1987): Elymus canadensis Linn'us and E. trachycaulus (Link) Gould ex Shinners (as R. pauciflora (Schweinitz) Hylander).
Löve (Feddes Repert. 95: 447–473. 1984) published several new combinations and nomina nova in Elymus based on names previously validly published in Roegneria by Keng and Chen (Acta Univ. Nankin. Sci. Nat. [J. Nanjing Univ. (Biol.)] 1963(1): 1–92. 1963). However, in all cases, Löve cited the place of publication of the basionym from a later publication by Keng (Fl. Ill. Pl. Prim. Sin. Gram., ed. 2, 1965). Under Art. 33.3 of the Saint Louis Code, Löve's combinations were not validly published. These errors in citation are not correctable under Art. 33.4 because they are omissions, nor are they correctable under Art. 33.6(a) because conditions for valid publication were not again fulfilled in the 1965 work.
All species of this genus are good forage plants.
About 170 species:temperate regions of both hemispheres, mainly in Asia; 88 species (62 endemic) in China.