Elymus glabriflorus
Elymus ×pseudorepens
southeastern wild-rye
false quackgrass
60-140 cm, erect;
nodes 6-9, mostly concealed, glabrous.
30-100 cm, ascending or erect, glabrous, mostly smooth, sometimes scabrous below the nodes.
evenly distributed;
sheaths glabrous or pubescent, often reddish brown;
auricles absent or to 2 mm, usually purplish brown;
ligules shorter than 1 mm;
blades 7-15 mm wide, lax or somewhat involute and ascending, usually dull green, sometimes with a glaucous bloom, adaxial surfaces glabrous or densely short-villous.
evenly distributed;
sheaths glabrous;
ligules to 0.5 mm;
blades 10-25 cm long, 2-7 mm wide, involute when dry, both surfaces scabrous, adaxial surfaces sparsely pilose, hairs 0.7-1 mm.
6-20 cm long, (2) 2.5-4(5.5) cm wide, erect, exserted, with (10)18-30(36) nodes, usually with 2(3) spikelets per node, occasionally with up to 5 at some nodes;
internodes 3-5 mm long, 0.3-0.8 mm thick and usually 4-angled at the thinnest sections, glabrous or pubescent beneath the spikelets.
5.5-13 cm long, 0.4-0.6 cm wide, with 1 spikelet per node;
internodes 3.5-5 mm.
10-20 mm, strongly divergent, often reddish brown at maturity, with (2)3-5(6) florets, lowest florets functional;
disarticulation below the glumes and each floret, or the lowest floret often falling with the glumes.
equal or subequal, entire, the basal 1-3 mm terete, indurate, moderately bowed out, without evident venation, glume bodies 7-18 mm long, (0.7)0.9-1.7 mm wide, linear-lanceolate, widening above the base, (3)4-5(7)-veined, smooth or scabrous, sometimes hirsute, margins firm, awns (10)15-25(30) mm, straight except the awns of the lowest spikelets frequently contorted;
lemmas 6-13 mm, smooth, scabrous, or hirsute, awns (15)25-35(40) mm, straight except the awns of the lowest spikelets occasionally contorted;
paleas 6-12 mm, obtuse;
anthers 2-4 mm.
8-18 mm, equaling or exceeded by the adjacent lemmas, more or less flat, 5-9-veined, margins unequal, the wider margins to about 0.3 mm, narrowly acute, sometimes awned, awns to 1 mm;
lemmas 7.5-15 mm, smooth and glabrous proximally, scabrous distally, mucronate or awned, awns to 3 mm;
anthers 1.5-2 mm.
usually mid-June to late July.
= 28.
Elymus glabriflorus
Elymus ×pseudorepens
Elymus glabriflorus grows on moist, damp, or dry soil in open woods, thickets, and tall grasslands, sometimes spreading into old fields and roadsides. It is found in most of the southeastern United States, extending north to Iowa, Illinois, Indiana, West Virginia, and along the Atlantic coast to Maine; it is rare north of Maryland. Anthesis is usually 2-4 weeks later than in E. virginicus (see next) and other sympatric taxa, even in Texas, where it occurs up to a month earlier than the dates given (Davies 1980).
Elymus glabriflorus varies greatly in its pubescence, but without clear taxonomic relevance. Plants that combine pubescent spikelets and, usually, pubescent leaves with somewhat shorter spikes (6-12 cm versus 9-20 cm) and lemmas (6-10 mm versus 7-13 mm) are typical on relatively dry, infertile soils, especially in hilly interior regions, and are less frequent on the southeastern coastal plain. They have been named E. glabriflorus var. australis (Scribn. & C.R. Ball) J.J.N. Campb. In contrast, glabrous to scabrous plants that are often more robust usually grow on relatively moist or damp soils of bottomlands and upland depressions.
Elymus glabriflorus is most closely related to E. macgregorii (see previous) and E. virginicus, forming occasional hybrids with both (Campbell 2000). It is sometimes confused with E. villosus (p. 302), from which it differs in having erect spikes, and glumes that are bowed out and disarticulate at maturity. It has also been confused with E. canadensis, especially E. canadensis var. robustus (p. 305), which may be derived from introgressants between the two species (Davies 1980). Hybrids with E. hystrix (p. 316) are also known, with apparent introgression at some range margins. Artificial crosses with other species failed in several cases (Church 1967a, 1967b).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Elymus ×pseudorepens consists of hybrids between E. lanceolatus (p. 327) and E. trachycaulus (p. 321). It appears to be fairly common, having been reported from Alberta to Michigan and south to Arizona, New Mexico, and Arkansas.
Elymus ×pseudorepens is an Elymus named hybrid
Elymus is notorious for its ability to hybridize. Most of its interspecific hybrids are partially fertile, permitting introgression between the parents. The descriptions provided below are restricted to the named interspecific hybrids. They should be treated with caution and some skepticism; some are based solely on the type specimen, because little other reliably identified material was available. Moreover, as the descriptions of the non-hybrid species indicate, many other interspecific hybrids exist.
The parentage of all hybrids is best determined in the field. Perennial hybrids, such as those in Elymus, can persist in an area after one or both parents have died out, but the simplest assumption is that both are present. Interspecific hybrids of Elymus that have disarticulating rachises presumably have E. elymoides or E. multisetus as one of their parents.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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