Elymus macgregorii
Elymus glabriflorus
early wild-rye
southeastern wild-rye
40-120 cm, erect or slightly decumbent;
nodes 4-8, mostly exposed, glabrous.
60-140 cm, erect;
nodes 6-9, mostly concealed, glabrous.
evenly distributed;
sheaths usually glabrous, rarely villous;
auricles 2-3 mm, usually purplish black when fresh, sometimes light brown;
ligules shorter than 1 mm;
blades 7-15 mm wide, lax, dark glossy green under the glaucous bloom, adaxial surfaces usually glabrous, occasionally villous.
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.
4-12 cm long, (1.7)2.2-3(4)4 cm wide, erect, exserted, with (6)9-16(20) nodes and 2 spikelets at all or most nodes, sometimes with 3 at some nodes;
internodes 4-7 mm long, about 0.3 mm thick and 2-angled at the thinnest sections, usually glabrous or scabridulous beneath the spikelets.
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.
10-15 mm, strongly divergent, glaucous, maturing to pale yellowish brown, with (2)3-4 florets, lowest florets functional;
disarticulation below the glumes and each floret, the lowest floret often falling with the glumes.
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.
subequal, entire, the basal 1-3 mm terete or subterete, indurate, without evident venation, moderately bowed out, glume bodies 8-16 mm long, 1-1.8 mm wide, linear-lanceolate, widening or parallel-sided above the base, (2)4-5(8)-veined, usually glabrous, occasionally hirsute, sometimes scabrous, margins firm, awns (10)15-20(25) mm, straight except the awns of the lowest spikelets occasionally contorted;
lemmas 6-12 mm, usually glabrous, sometimes scabrous, occasionally villous, awns (15)20-30 mm, straight;
paleas 6-10 mm, apices obtuse;
anthers 2-4 mm.
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.
usually mid-May to mid-June.
usually mid-June to late July.
= 28.
= 28.
Elymus macgregorii
Elymus glabriflorus
Elymus macgregorii grows in moist, deep, alluvial or residual, calcareous or other base-rich soils in woods and thickets, mostly east of the 100th Meridian in the contiguous United States. It used to be confused with E. glabriflorus (p. 296) or E. virginicus (p. 298), but it reaches anthesis about a month earlier than sympatric populations of these species. In most of its range, E. macgregorii has purplish black auricles; light brown auricles may be locally abundant, particularly in populations at the limits of its range.
Elymus macregorii hybridizes with several species, but especially E. virginicus and E. hystrix (p. 316) (Campbell 2000). Western plants often have smaller, more condensed spikes and distinctly villous leaves, suggesting a transition to E. virginicus var. jejunus (p. 300). Transitions to E. virginicus var. jejunus can also be recognized to the north, where the dates of anthesis are delayed, but even in Maine, E. macgregorii reaches anthesis about 10 days earlier than E. virginicus (Campbell and Haines 2002). Plants with villous lemmas grow at scattered locations; they have not been reported in distinct habitats, nor in large enough populations to warrant taxonomic recognition.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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.)
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