13.11 ×PSEUDELYMUS Barkworth & D.R. Dewey

Mary E. Barkworth

Plants perennial; sometimes rhizomatous. Culms 50–80 cm, erect, glabrous. Leaves not basally concentrated; sheaths glabrous or puberulent; auricles present; ligules truncate; Inflorescences distichous spikes, with 1(2) spikelet(s) per node. Spikelets appressed, with 3–5 florets. Glumes unequal, linear-lanceolate to lanceolate; lemmas awned or unawned; paleas slightly shorter than to slightly longer than the lemmas; anthers indehiscent.

×Pseudelymus comprises hybrids between Pseudoroegneria and Elymus. Only one species is treated here. Another species, Elymus albicans, is thought to be a similar hybrid but it is treated as a species because it is frequently fertile.

SELECTED REFERENCE Dewey, D.R. 1964. Natural and synthetic hybrids of Agropyron spicatum × Sitanion hystrix. Bull. Torrey Bot. Club 91:396–405.

1. ×Pseudelymus saxicola (Scribn. & J.G. Sm.) Barkworth & D.R. Dewey

Plants not rhizomatous. Culms 0.8–1 mm thick; ligules 0.2–0.4 mm; blades 1.5–2 mm wide. Spikes 7–14 cm, with 1 spikelet per node; internodes 7–9 mm. Spikelets 12–20 mm excluding the awns; disarticulation beneath the florets, sometimes also in the rachises. Glumes 15–30 mm including the awns, glume bodies 6–8 mm long, 0.7–1 mm wide, (1)3–4-veined; lemmas 10–15 mm excluding the awns, (14)18–40 mm including the awns, apices often bifid; anthers about 2.5 mm.

×Pseudelymus saxicola consists of hybrids between Pseudoroegneria spicata and Elymus elymoides. It is a rather common hybrid in western North America. It differs from E. albicans, which is thought to be derived from hybrids between P. spicata and E. lanceolatus, in lacking rhizomes, having longer awns on its glumes and lemmas, and having disarticulating rachises. It is more likely to be confused with E. ×saundersii, but differs in its longer glume and lemma awns.