Elymus macgregorii
Elymus dahuricus
early wild-rye
Dahurian wild rye
40-120 cm, erect or slightly decumbent;
nodes 4-8, mostly exposed, glabrous.
30-130 cm, erect;
nodes 4-7, mostly exposed, usually glabrous, occasionally short-hairy.
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;
auricles minute or absent;
ligules 0.5-1 mm;
blades 3-18 mm wide, lax, usually pale green, sometimes glaucous, adaxial surfaces usually smooth or scabrous on the veins, sometimes sparsely pilose.
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.
7-23 cm long, 1-2.5 cm wide, usually slightly nodding, sometimes erect, usually with 2 spikelets per node, occasionally with 1 spikelet at some nodes;
internodes 3-6 mm long, 0.2-0.8 mm thick at the thinnest sections, angles usually with scattered hairs.
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.
10-15 mm, appressed to divergent, often purplish, with (2)3-4(5) florets, lowest florets functional;
disarticulation above the glumes, beneath each floret.
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, the bases flat, not indurate, veins evident, glume bodies 6-9 mm long, 1-1.5 mm wide, linear-lanceolate, entire, widening or parallel-sided above the base, (1)3-5(7)-veined, veins scabrous, margins hyaline or scarious, awns (0)1-5 mm, straight or outcurving;
lemmas (5)7-11 mm, usually glabrous and smooth throughout, sometimes scabrous to hispid distally and on the margins, marginal hairs not markedly longer than those elsewhere, awns (3)6-17(20) mm, usually somewhat outcurving from near the base;
paleas 7-11 mm, keels spinose-ciliate, apices obtuse or truncate;
anthers 1.5-3.5 mm.
usually mid-May to mid-June.
from May to July.
= 28.
= 42.
Elymus macgregorii
Elymus dahuricus
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 dahuricus is widespread in temperate central and eastern Asia. Like E. tsukushiensis (p. 336), it is a hexaploid with an StYH genome constitution. It has been introduced for reclamation in some parts of western North America. It is most likely to be confused with E. glaucus (p. 306), from which it differs in its palea shape. Because its presence in the region became known shortly before completion of this volume, its distribution in the region is not known. Several varieties have been described in Asia; only Elymus dahuricus Turcz. ex Griseb. var. dahuricus has been introduced to North America.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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