Elymus canadensis
Elymus interruptus
Canada wild rye, Canadian wild rye, Great Plains wild-rye, élyme du Canada
Southwestern wildrye
(40)60-150(180) cm, erect or decumbent;
nodes 4-10, mostly concealed by the leaf sheaths, glabrous.
usually (40)60-100(120) cm, erect or the bases somewhat decumbent;
nodes 4-8, usually exposed, glabrous.
evenly distributed;
sheaths smooth or scabridulous, glabrous or hirsute, often reddish brown;
auricles 1.5-4 mm, brown or purplish black;
ligules to 1(2) mm, truncate, ciliolate;
blades (3)4-15(20) mm wide, usually firm, often ascending and somewhat involute, usually dull green, drying to grayish, adaxial surfaces usually smooth or scabridulous and glabrous, rarely sparsely hispid to villous.
evenly distributed;
sheaths usually glabrous, occasionally hirsute;
auricles 0-2 mm, pale or reddish brown;
ligules to 1 mm;
blades 3-9 mm wide, lax, pale green, adaxial surfaces densely short-pilose, hispidulous, or scabridulous, especially on the veins.
6-30 cm long, 3-7 cm wide, usually nodding, sometimes pendent or almost erect, usually with 2(3) spikelets per node, occasionally to 5 at some nodes, rarely with 1 at some nodes but never throughout;
internodes (2)3-5(7) mm long, or 5-10 mm long towards the base, 0.2-0.35 mm thick at the thinnest sections, glabrous or with a few hairs below the spikelets.
5-20 cm long, 2-5 cm wide, erect to slightly nodding, with 2 spikelets per node;
internodes (5)8-14 mm long, 0.2-0.3 mm thick at the thinnest sections, without pronounced dorsal angles, often with green lateral bands, glabrous beneath the spikelets.
12-20 mm excluding the awns, more or less divergent, with (2)3-5(7) florets, lowest florets functional;
disarticulation usually above the glumes and beneath each floret, rarely also below the glumes.
(6)9-15(22) mm, somewhat to strongly divergent, with 2-5 florets, lowest florets functional;
disarticulation above the glumes and beneath each floret.
usually equal, occasionally subequal, 11-40 mm including the awns, the basal 0-1 mm subterete and slightly indurate, glume bodies 6-13 mm long, 0.5-1.6 mm wide, linear-lanceolate to subsetaceous, entire, widening or parallel-sided above the base, 3-5-veined, glabrous to scabrous-ciliate, rarely villous on the veins, margins firm, awns (5)10-25(27) mm, straight to outcurving;
lemmas 8-15 mm, glabrous, scabrous, hispid, or uniformly villous with the hairs generally appressed, awns (10)15-40(50) mm, moderately to strongly outcurving, often contorted at the spike bases;
paleas 7-13 mm, acute, usually bidentate;
anthers 2-3.5 mm.
subequal, 15-30 mm including the weakly differentiated awns, the basal 0-1 mm subterete and indurate, glume bodies, when distinguishable, about 6-10 mm long, (0.2)0.3-0.5(0.7) mm wide, linear-setiform to setaceous, entire, widening or parallel-sided above the base, 1-3-veined, glabrous or scabridulous, margins firm, awns straight or flexuous;
lemmas 7-10 mm, smooth or scabridulous, occasionally hirtellous especially near the margins, awns 15-22 mm, straight to moderately outcurving;
paleas 6-9 mm, obtuse or narrowly truncate, sometimes emarginate;
anthers 2-4.5 mm.
May to July.
May to July.
= 28, rarely 42.
= 28.
Elymus canadensis
Elymus interruptus
Elymus canadensis grows on dry to moist or damp, often sandy or gravelly soil on prairies, dunes, stream banks, ditches, roadsides, and disturbed ground, or, especially to the south, in thickets and open woods near streams. It is widespread in most of temperate North America, extending from the southwestern Northwest Territories to Coahuila, Mexico, being especially common in the Great Plains. Reports from California and the southeastern states appear to be based on misidentifications. E. canadensis is considered a good forage species.
Elymus canadensis is sometimes confused with E. riparius (see previous), from which it differs in having curved rather than straight awns; and with E. wiegandii (p. 305), from which it differs in its less robust habit and narrower leaves. It can hybridize with E. glabriflorus (p. 296), E. virginicus (p. 298), E. hystrix (p. 316) and allies, E. glaucus (p. 306), E. trachycaulus (p. 321), Pseudoroegneria spicata (p. 281), and other species. Subsequent introgression may have contributed to much of the diversity within the genus (Pohl 1959; Brown and Pratt 1960; Nelson and Tyrl 1978; Davies 1980; Campbell 2002). The three varieties recognized here show clear differences in their typical expression and evidence some geographic separation, but they may prove to be artificial reference points within a more or less continuous variation (Sanders et al. 1979). Nevertheless, crossing barriers sometimes exist between the varieties, and even between some sympatric strains (Church 1954, 1958, 1967a).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Elymus interruptus grows in dry to moist, rocky soil, often in canyons, open woods, and thickets, in the southwestern United States and northern Mexico. Apparent intermediates between E. interruptus and E. canadensis (p. 303) have been collected north of the documented range of typical E. interruptus in Arizona, New Mexico, and Iowa. Plants in the Ozark and Ouachita mountains, especially in Arkansas, that were previously referred to E. interruptus are now included in E. churchii (p. 314).
Elymus interruptus is a poorly understood southern species that, at one extreme, used to be included in E. canadensis or, at the other extreme, used to include E. churchii, E. svensonii (p. 314), and E. diversiglumis (p. 316), three species that seem more closely allied to E. hystrix (p. 316). Campbell (2002) suggested E. interruptus may have arisen from the introgression of E. hystrix or a related species into E. canadensis var. brachystachys. Artificial crosses between E. hystrix and E. canadensis were generally unsuccessful, but yielded some plants resembling E. interruptus (Church 1954). Elymus interruptus has been crossed with E. canadensis, E. hystrix, E. svensonii, E. virginicus (p. 298), E. glabriflorus (p. 296) and E. diversiglumis; only the hybrids with E. diversiglumis were completely sterile (Church 1954, 1967a; Brown and Pratt 1960).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Lemmas usually villous or hispid; spikes nodding to almost pendent; internodes 4-7 mm long, often strongly glaucous | var. canadensis |
1. Lemmas usually smooth or scabridulous, occasionally hirsute; spikes usually nodding, occasionally almost erect; internodes 3-4 mm long, not strongly glaucous. | → 2 |
2. Glumes not clearly indurate or bowed out at the base, awns 10-20 mm long; lemmas smooth or scabridulous, awns usually 20-30 mm long, moderately outcurving; spikes 6-20 cm long | var. brachystachys |
2. Glumes often slightly indurate and bowed out at the base, awns 15-25 mm long; lemmas occasionally hirsute, awns 30-40 mm long, often strongly outcurving; spikes 15-25(30) cm long | var. robustus |
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