Elymus glabriflorus
Elymus semicostatus
southeastern wild-rye
drooping wildrye
60-140 cm, erect;
nodes 6-9, mostly concealed, glabrous.
45-135 cm, erect or geniculately ascending, glabrous.
glabrous or villous;
auricles to 1.5 mm;
ligules 0.5-1.5 mm, truncate;
blades 15-30 cm long, 4-12 mm wide, sometimes villous, adaxial surfaces smooth or scabrous, primary and secondary veins alternating.
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.
8-30 cm long, 1-2 cm wide including the awns, 0.5-1 cm wide excluding the awns, erect or nodding, usually with 1 spikelet per node, sometimes with 2 spikelets at the lower nodes;
internodes 10-20 mm long, about 0.8 mm wide, scabrous on the margins and on the surfaces, marginal prickles larger than those on the surfaces, hirtellous just 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.
16-30 mm, loosely appressed, with 6-8 florets;
rachilla internodes about 0.8 mm, strigose, hairs to about 0.3 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.
subequal, 10-18 mm long, 1.1-2 mm wide, elliptic-lanceolate, green, not keeled, 5-7-veined, veins more or less equally prominent, scabrous, apices acute to acuminate;
lemmas 10-14 mm, scabrous or puberulent dorsally, awned, awns (4)12-18 mm, straight;
paleas 3/4 as long as to slightly shorter than the lemmas, keels outwardly curved below the apices, apices 0.3-0.7 mm wide, truncate;
anthers 3-6 mm.
usually mid-June to late July.
= 28.
= 28.
Elymus glabriflorus
Elymus semicostatus
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 semicostatus is native to central Asia, from Afghanistan through Pakistan to northeastern India (Sikkim). Reports of its presence in the Flora region appear to be based on misidentifications.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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