Elymus glabriflorus
Elymus macrourus
southeastern wild-rye
northern wheatgrass, tuft wheatgrass
60-140 cm, erect;
nodes 6-9, mostly concealed, glabrous.
35-100 cm, ascending to erect;
nodes sometimes pubescent.
glabrous;
auricles absent;
ligules 0.5-1 mm, truncate to rounded;
blades 3-10 mm wide, flat, usually glabrous, abaxial surfaces smooth or scabridulous, adaxial surfaces scabrous.
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.
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.
5-20 cm long, 0.4-0.8 cm wide, erect, with 1 spikelet per node;
internodes 7-8 mm long, about 0.5 mm wide, glabrous below the spikelets.
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.
12-20 mm, appressed, with 4-7 florets;
rachillas hairy, hairs 0.3-0.5 mm;
disarticulation above the glumes, beneath each floret.
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.
6-10 mm long, 1/3-2/3 the length of the spikelets and to about 1/2 the length of the adjacent lemmas, 0.8-1.8 mm wide, widest at about midlength, lanceolate, flat, rounded, or symmetrically keeled, usually green or green tinged with purple, 3-4-veined, veins scabridulous, scabrous, or with hairs to 0.3 mm, usually glabrous elsewhere, margins subequal, about 0.3 mm wide, widest near midlength, apices acute, unawned or awned, awns to 1 mm;
lemmas 8-12 mm, hairy throughout or glabrous distally, hairs all alike, 0.2-0.3 mm, apices unawned or awned, awns to 7 mm, straight;
paleas subequal to the lemmas, tapering to the apices, apices about 0.8 mm wide;
anthers 1-2 mm.
usually mid-June to late July.
= 28.
= 28.
Elymus glabriflorus
Elymus macrourus
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 macrourus grows on river banks and bars, lake shores, and hillsides in northwestern North America. Outside of North America, it grows across the Russian arctic, and extends south into the boreal forest. Plants growing on shifting river banks and bars often appear rhizomatous, as the lower internodes elongate in response to the disturbed substrate. Plants of E. macrourus differ from E. alaskanus (see next) in the shape of their glumes and their narrower glume margins, and from E. trachycaulus (p. 321) in their relatively short glumes and evidently hairy rachilla segments.
Three varieties of Elymus macrourus are recognized in Russian treatments. It is not clear to which, if any, of the Russian varieties North American plants belong. A circumboreal study is needed, using plants grown from seeds collected in the wild. Seeds available as E. macrourus through germplasm resources appear to be misidentified.
Elymus macrourus is one of the parents in both E. ×palmerensis (p. 340) and ×Elyhordeum pilosilemma (p. 284).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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