Plants perennial; sometimes cespitose, sometimes rhizomatous, sometimes stoloniferous. Culms 8-180(220) cm, usually erect to ascending, sometimes strongly decumbent to prostrate, usually glabrous. Leaves usually evenly distributed, sometimes somewhat basally concentrated; sheaths open for most of their length; auricles often present; ligules membranous, usually truncate or rounded, sometimes acute, entire or erose, often ciliolate; blades 1-24(25) mm wide, abaxial surfaces usually smooth or scabrous, sometimes with hairs, adaxial surfaces scabrous or with hairs, particularly over the veins, usually with unequal, not strongly ribbed, widely spaced veins, sometimes with equal, strongly ribbed, closely spaced veins. Inflorescences spikes, usually exserted, with 1-3(5) spikelets per node, internodes (1.5)2-26 mm; rachises with scabridulous, scabrous, or ciliate edges. Spikelets usually appressed to ascending, sometimes strongly divergent or patent, with 1-11 florets, the lowest florets usually functional, sterile and glumelike in some species, the distal florets often reduced; disarticulation usually above the glumes and beneath each floret, sometimes also below the glumes or in the rachises. Glumes usually 2, absent or highly reduced in some species, usually equal to subequal, sometimes unequal, usually linear-lanceolate to linear, setaceous, or subulate, sometimes oblanceolate to obovate, (0)1-7-veined, sometimes keeled over 1 vein, not necessarily the central vein, keel vein sometimes extending into an awn; lemmas linear-lanceolate, obscurely 5(7)-veined, apices acute, often awned, sometimes bidentate, teeth to 0.2 mm, sometimes with bristles, bristles to 10 mm, awns terminal or from the sinus, straight or arcuately divergent, not geniculate; paleas from shorter than to slightly longer than the lemmas, keels scabrous or ciliate, at least in part; anthers 3, 0.7-7 mm. Caryopses with hairy apices, x = 7. Haplomes St, H, Y, P.

Distribution

Idaho, Mont., Nebr., N.C., Conn., N.J., N.Y., Mass., Wash., Va., W.Va., Ark., Iowa, Kans., Mo., N.Dak., Okla., S.Dak., Ariz., D.C, Ga., Ill., Ky., Mich., N.Mex., Pa., S.C., Tenn., Wyo., Del., Miss., Ind., Oreg., Maine, N.H., R.I., Vt., Ala., Fla., La., Md., N.S., Ohio, Tex., Wis., Colo., Calif., Alaska, Utah, Nev., Alta., B.C., Greenland, Man., N.B., Nfld. and Labr., N.W.T., Nunavut, Ont., P.E.I., Que., Sask., Yukon, Minn.

Discussion

Name from the Greek elyo, 'rolled up', the caryopses being tightly embraced by the lemma and palea.

All species of Elymus are alloploids that combine one copy of the St haplome present in Pseudoroegneria with at least one other haplome. So far as is known, all species that are native to North America, as well as many species native to northern Eurasia, are tetraploids with one additional haplome, the H genome from Hordeum sect. Critesion. Many Asian species combine the St haplome with the Y haplome, for which there are no known diploids; such species are sometimes placed in the segregate genus Roegneria. This treatment includes two such species, E. ciliaris and E. semicostatus. In addition, the treatment includes two hexaploid species, E. tsukusbiensis and E. dahuricus, that combine all three haplomes. Elymus repens and E. hoffmannii, the other two hexaploid species in this treatment, basically combine two copies of the St haplome with one of the H haplome, but the molecular data for E. repens point to a more complex situation (Mason-Gamer 2001). For further discussion of generic delimitation in the Triticeae, see Barkworth (2000), Yen et al. (2005), and Barkworth and von Bothmer (2005).

Elymus is sometimes divided into multiple sections (see, for example, Tsvelev 1976; Love 1984). There are, however, no detailed morphological descriptions of the sections, making it difficult to determine how to treat the North American species. It is notable that the species with solitary spikelets are concentrated in western and northern North America, whereas the species with multiple spikelets at a node are most prevalent east of the Rocky Mountains, from southern Canada to the Gulf Coast. There are exceptions to this statement. For instance, species with multiple spikelets and disarticulating rachises are primarily western in their distribution, yet E. glaucus, a species with multiple spikelets and non-disarticulating rachises, is western. Like the western species with solitary spikelets, and unlike most eastern species, its glumes have a hyaline margin.

Selected References

Key

1 Spikelets 1 at all or most nodes; glumes with flat, non-indurate bases, glume bodies linear-lanceolate to obovate, margins hyaline, scarious, or chartaceous; lemmas awned or unawned [for opposite lead, see p. 292]. > 2
2 Anthers 3-7 mm long; plants often strongly rhizomatous, sometimes not or only weakly rhizomatous. > 3
3 At least some lemmas with strongly divergent, outcurving, or recurved awns. > 4
4 Culms prostrate to decumbent and geniculate, 20-50 cm tall; plants of subalpine and alpine habitats Elymus sierrae
4 Culms erect or decumbent only at the base, (15)40-130 cm tall; plants of valley and montane, but not subalpine or alpine, habitats. > 5
5 Plants strongly rhizomatous; blades 1-3 mm wide Elymus albicans
5 Plants cespitose or weakly rhizomatous; blades 1.5-6 mm wide. > 6
6 Spikes often drooping to pendent at maturity; rachis internodes 11-17 mm long; plants of the southwestern United States Elymus arizonicus
6 Spikes erect to slightly nodding at maturity; rachis internodes 5-12 mm long; plants of the northwestern contiguous United States Elymus wawawaiensis
3 Lemmas unawned or with straight to flexuous awns. > 4
7 Lemmas 12-14 mm long; plants not or weakly rhizomatous. > 8
8 Palea keels straight or slightly outwardly curved below the apices, apices about 0.2 mm wide between the vein ends Elymus glaucus
8 Palea keels distinctly outwardly curved below the apices; apices 0.3-0.7 mm wide between the vein ends Elymus semicostatus
7 Lemmas 7-12 mm long; plants not, weakly, or strongly rhizomatous. > 8
9 Glumes keeled distally, keels smooth and inconspicuous proximally, scabrous and conspicuous distally; lemmas glabrous. > 10
10 Adaxial surfaces of the blades usually sparsely pilose, sometimes glabrous, veins smooth, the primary veins separated by secondary veins; plants strongly rhizomatous Elymus repens
10 Adaxial surfaces of the blades glabrous, veins smooth or scabrous, all veins more or less equally prominent; plants slightly to moderately rhizomatous Elymus hoffmannii
9 Glumes not keeled or keeled throughout their length, keels smooth or scabrous throughout, sometimes hairy, conspicuous or not; lemmas glabrous or hairy. > 10
11 Plants strongly rhizomatous; glumes 5-9 mm long; lemmas densely to sparsely hairy or glabrous Elymus lanceolatus
11 Plants cespitose or weakly rhizomatous; glumes 6-19 mm long; lemmas glabrous or pubescent, never densely hairy. > 12
12 Spikelets usually at least twice as long as the internodes; internodes 4-12 mm long; glumes often awned, sometimes unawned; blades usually lax Elymus glaucus
12 Spikelets from shorter than to almost twice as long as the internodes; internodes 9-27 mm long; glumes unawned; blades usually straight Elymus stebbinsii
2 Anthers 0.7-3 mm long; plants usually not or weakly rhizomatous, sometimes strongly rhizomatous. > 3
13 Culms prostrate or strongly decumbent at the base; disarticulation in the rachises or beneath the florets; plants of subalpine, alpine, and arctic habitats. > 14
14 Glumes unawned or with awns to 1 mm long; plants of arctic habitats Elymus alaskanus
14 Glumes awned, awns 3-30 mm long; plants of subalpine and alpine habitats. > 15
15 Anthers 1-1.6 mm long; internodes 2.5-5(7) mm long; disarticulation initially in the rachises; spikelets appressed to ascending Elymus scribneri
15 Anthers 2-3.5 mm long; internodes 5-15 mm long; rachises not disarticulating; spikelets ascending to divergent Elymus sierrae
13 Culms usually ascending to erect, sometimes geniculate or weakly decumbent at the base; disarticulation beneath the florets; plants of sea level to subalpine habitats. > 14
16 Lemmas with coarse, stiff, marginal hairs up to 1 mm long; paleas 2/3 – 4/5 as long as the lemmas, with wide, rounded apices Elymus ciliaris
16 Lemmas with the marginal hairs, if present, similar to those elsewhere on the lemma; paleas 3/4 as long as to slightly longer than the lemmas, tapering to the apices. > 17
17 Lemmas awned, awns 7-40 mm long. > 18
18 Lemma awns strongly arcuate to outcurving or recurved. > 19
19 Spikes 8-12 cm long, straight, erect or inclined; blades 2-4 mm wide Elymus bakeri
19 Spikes 7-30 cm long, flexuous, nodding to pendent; blades 5-14 mm wide Elymus sibiricus
18 Lemma awns usually straight or flexuous, or, if shorter than 10 mm, sometimes weakly curving. > 19
20 Glumes with hairs on the adaxial (inner) surface, these often inconspicuous Elymus caninus
20 Glumes glabrous on the adaxial (inner) surface. > 21
21 Palea keels distinctly outwardly curved below the apices, winged, not or scarcely extending beyond the intercostal region; apices 0.3-0.5 mm wide Elymus tsukushiensis
21 Palea keels straight or slightly outwardly curved below the apices, not winged, often extending beyond the intercostal region, sometimes forming teeth; apices 0.1-0.3 mm wide. > 22
22 Glumes 1.8-2.3 mm wide, margins 0.2-0.3 mm wide Elymus trachycaulus
22 Glumes 0.4-1.5(2) mm wide, margins 0.1-0.2 mm wide. > 23
23 Spikes erect or almost so, 0.5-2 cm wide Elymus glaucus
23 Spikes nodding to pendent, 2-5 cm wide Elymus sibiricus
17 Lemmas unawned or with awns up to 7 mm long. > 18
24 Plants strongly rhizomatous Elymus lanceolatus
24 Plants not or only shortly rhizomatous. > 25
25 Glumes 1/3 – 2/3 as long as the adjacent lemmas. > 26
26 Glumes 0.8-1.8 mm wide, lanceolate, margins subequal; lemmas evenly hairy or glabrous distally Elymus macrourus
26 Glumes 1.5-2 mm wide, oblanceolate to obovate, margins unequal; lemmas glabrous, evenly hairy, or more densely hairy distally Elymus alaskanus
25 Glumes 3/4 as long as to slightly longer than the adjacent lemmas. > 26
27 Glumes 3(5)-veined; glume margins unequal, the wider margins 0.3-1 mm wide, usually widest in the distal 1/3; lemma awns 0.5-3 mm long Elymus violaceus
27 Glumes 3-7-veined, glume margins equal, 0.1-0.5 mm wide, widest at or slightly beyond midlength; lemmas unawned or with awns to 40 mm long. > 28
28 Glumes 1.8-2.3 mm wide, margins 0.2-0.3 mm wide Elymus trachycaulus
28 Glumes 0.4-1.5(2) mm wide, margins 0.1-0.2 mm wide Elymus glaucus
1 Spikelets 2-3(5) at all or most nodes; glumes often with subterete to terete, indurate bases, sometimes with flat, non-indurate bases, glume bodies linear-lanceolate to setaceous or subulate, margins usually firm, sometimes hyaline or scarious; lemmas usually awned, awns up to 120 mm long [for opposite lead, see p. 290]. > 2
29 Rachises disarticulating at maturity; glumes 10-135 mm long including the awns, sometimes split longitudinally, flexuous to outcurving from near the base; lowest floret in each spikelet sometimes sterile; blades 1-6 mm wide. > 30
30 Glume awns split into 3-9 divisions; lemma awns about 0.2 mm wide at the base; rachis internodes 3-5 mm long Elymus multisetus
30 Glume awns entire or split into 2-3 divisions; lemma awns about 0.4 mm wide at the base; rachis internodes 3-10(15) mm long Elymus elymoides
29 Rachises not disarticulating at maturity; glumes 0-43 mm long including the awns, entire, straight or outcurving from well above the base; lowest floret in each spikelet functional; blades 2-25 mm wide. > 30
31 Glume bodies with 0-1(2) veins, linear or tapering from the base, 0.1-0.6 mm wide, 0-24 mm long including the awns, often differing in length by more than 5 mm, persistent after the florets disarticulate; rachis internodes 0.1-0.3(0.4) mm thick at the thinnest sections, often with green lateral bands. > 32
32 Spikelets widely divergent to patent at maturity; lemma awns usually straight, rarely slightly curving; glumes vestigial or 1-3 mm long, occasionally some unequal glumes up to 10(20) mm long and 0.1-0.2 mm wide but with no distinct vein; spikes more or less erect Elymus hystrix
32 Spikelets usually appressed, never widely divergent; lemma awns straight or curving; glumes sometimes vestigial, usually 1-24 mm long, 0.1-0.6 mm wide, often with 1(2) distinct veins; spikes erect, nodding, or pendent. > 33
33 Glumes 12-30 mm long including the awns, subequal; lemma awns straight to moderately curving; spikes erect to slightly nodding. > 34
34 Spikelets (6)9-15(22) mm long excluding the awns, each with 2-5 florets; lemma awns moderately outcurving at maturity; glumes (0.2)0.3-0.5(0.7) mm wide Elymus interruptus
34 Spikelets 18-40 mm long excluding the awns, each with 3-8 florets; lemma awns straight to slightly curving at maturity; glumes 0.1-0.3(0.6) mm wide. > 35
35 Anthers 2.5-4 mm long; lemmas scabrous-hispid to thinly strigose, at least distally; spikes 4-12 cm long; internodes 3-6 mm long, without green lateral bands, with hispid dorsal angles Elymus pringlei
35 Anthers 4.5-6 mm long; lemmas smooth, glabrous; spikes 9-20 cm long; internodes (5)7-15(22) mm long, with green lateral bands, glabrous except for the ciliolate margins Elymus texensis
33 Glumes 0-15(30) mm long including the awns, usually differing in length by at least 4 mm, 1 or both shorter than 12 mm, sometimes both essentially absent; lemma awns outcurving at maturity; spikes more or less nodding. > 34
36 Rachis internodes 4-6(9) mm long; lemmas hirsute to strigose, at least near the margins, awns 20-35 mm long; sheaths glabrous; plants not glaucous or moderately glaucous Elymus diversiglumis
36 Rachis internodes (4)6-13(18) mm long; lemmas glabrous or pubescent, awns (8)10-30(35) mm long; sheaths glabrous or villous; plants usually glaucous, sometimes strongly so. > 37
37 Lemmas usually glabrous, veins occasionally hispidulous near the apices, awns (8)10-20(25) mm long; spikelets with (3)4-5 florets; rachis internodes (4)6-10(12) mm long, without green lateral bands, glabrous; adaxial surfaces of the blades usually villous; plants strongly glaucous Elymus svensonii
37 Lemmas usually hairy, awns (10)20-30(35) mm long; spikelets with 3(5) florets; rachis internodes (5)7-13(18) mm long, with green lateral bands and hispid dorsal angles; adaxial surfaces of the blades glabrous or short-pilose; plants somewhat glaucous Elymus churchii
31 Glume bodies with 2-5(8) veins, widening or parallel-sided above the base, (0.2)0.3-2.3 mm wide, 4-43 mm long including the awns, equal or subequal, persistent or disarticulating; rachis internodes 0.1-0.8 mm thick at the thinnest sections, usually lacking green lateral bands. > 32
38 Glumes bases more or less terete, indurate, and without veins for 0.5-4 mm; glume bodies exceeding the adjacent lemmas by 1-5 mm or indistinguishable from the glume awns; lemma awns usually straight, occasionally contorted on the lower spikelets; rachis internodes (1.5)2-5(8) mm long. > 39
39 Glumes persistent, glume bodies (0.2)0.3-0.8(1) mm wide, with 2-4 veins, the basal 0.5-2 mm straight or slightly curving; lemmas with hairs or scabrous; spikelets with 1-3(4) florets; spikes nodding, exserted from the sheath. > 40
40 Adaxial surfaces of the blades densely villous with fine whitish hairs, rarely just pilose on the veins, dark glossy green; spikes 4-12 cm long; internodes (1.5)2-3(4) mm long; spikelets with 1-2(3) florets; lemmas usually villous, sometimes glabrous, sometimes scabrous, 5.5-9 mm long, 0.5-1.5 mm longer than the paleas; anthesis usually in early June to early July Elymus villosus
40 Adaxial surfaces of the blades glabrous or scabrous, dull green; spikes 7-25 cm long; internodes 3-5(8) mm long; spikelets with 2-3(4) florets; lemmas hispidulous or scabrous, 7-14 mm long, 1-5 mm longer than the paleas; anthesis usually in late June to late July Elymus riparius
39 Glumes disarticulating, glume bodies (0.5)0.7-2.3 mm wide, with (2)3-5(8) veins, the basal 1-4 mm clearly bowed out; lemmas often glabrous, sometimes scabrous; spikelets with 2-5(6) florets; spikes erect, exserted or sheathed. > 40
41 Spikes (0.5)0.7-2.2(2.5) cm wide including the awns, exserted or sheathed; glume awns 0-10(15) mm long; spikelets appressed to slightly spreading; blades usually glabrous or scabridulous. > 42
42 Lemma awns 5-15(20) mm long at midspike; blades of all leaves usually spreading or lax and flat, those of the lower leaves not markedly larger or more persistent than those of the upper leaves; anthesis in mid-June to mid-August, usually 1-2 weeks earlier than sympatric E. curvatus Elymus virginicus
42 Lemma awns 0.5-3(4) mm long at midspike; upper blades usually ascending and somewhat involute, blades of the lower leaves relatively short, narrow, and senescing earlier than those of the upper leaves; anthesis usually in late June to early August, 1-2 weeks later than sympatric E. virginicus Elymus curvatus
41 Spikes (1.7)2.2-4.5(5.5) cm wide including the awns, exserted; glume awns (10)15-30 mm long; spikelets spreading; blades glabrous or villous. > 42
43 Spikes with (6)9-16(20) nodes; internodes 4-7 mm long, about 0.3 mm thick at the thinnest portion; blades lax, dark glossy green under the glaucous bloom; auricles 2-3 mm long, often purplish black, at least in the central range of the species; anthesis usually in mid-May to mid-June Elymus macgregorii
43 Spikes with (10)18-30(36) nodes; internodes 3-5 mm long, 0.3-0.8 mm thick at the thinnest portion; blades lax, or ascending and involute, usually dull green, with or without a glaucous bloom; auricles 0-2 mm long, usually purplish brown; anthesis usually in mid-June to late July Elymus glabriflorus
38 Glume bases flat and veined or, if subterete to terete, indurate and without veins for less than 1 mm; glume bodies shorter than or subequal to the lowest lemmas; lemma awns usually flexuous to curving, sometimes straight; rachis internodes (2)3-14 mm long. > 39
44 Glumes with more or less terete bases, without hyaline or scarious margins, always awned, awns (5)8-25(27) mm long or the glume bodies indistinguishable from the awns; spikelets (1)2-3(5) per node, spreading, not or rarely purplish; cauline nodes usually concealed by the sheaths. > 45
45 Spikes erect to slightly nodding, internodes (5)8-14 mm long; glumes 0.2-0.5(0.7) mm wide; lemmas 7-10 mm long, usually smooth or scabrous, occasionally hirtellous, especially near the margins, awns 15-22 mm long, straight to moderately outcurving; blades 3-9 mm wide; culms (40)60-100(120) cm tall, nodes usually exposed Elymus interruptus
45 Spikes usually nodding to pendent, sometimes erect, internodes (2)3-8(12) mm long; glume bodies (0.2)0.4-1.6 mm wide; lemmas 8-15 mm long, glabrous or uniformly hairy, awns (10)15-40(50) mm long, moderately to strongly outcurving; blades 3-24 mm wide; culms (40)60-180(220) cm tall, nodes usually concealed by the leaf sheaths. > 46
46 Rachis internodes (2)3-5(7) mm long; spikelets 2(3) at most nodes, occasionally 1 or up to 5 at some nodes; paleas acute; blades (3)4-15(20) mm wide, usually firm and somewhat involute, dull green, drying grayish Elymus canadensis
46 Rachis internodes 5-12 mm long; spikelets 2 per node; paleas narrowly truncate; blades (8)10-20(24) mm wide, flat, lax, dark green Elymus wiegandii
44 Glumes with flat bases and hyaline or scarious margins, usually awned, awns 1-10 mm long, sometimes unawned; spikelets (1)2(3) per node, appressed to divergent, sometimes purplish; cauline nodes mostly exposed. > 45
47 Anthers 0.9-1.7 mm long; glumes 3-8 mm long; lowest lemmas 3-6 mm longer than the glumes, densely scabridulous to scabrous, awns usually outcurving; spikelets with (3)4-5(7) florets; spikes 2-5 cm wide, nodding to pendent; cauline nodes glabrous Elymus sibiricus
47 Anthers 1.5-4.5 mm long; glumes (4.5)6-14(19) mm long; lowest lemmas from shorter than to 2.5 mm longer than the glumes, smooth, sometimes hairy, awns straight, flexuous, or outcurving; spikelets with 2-4(7) florets; spikes (0.2)0.5-2.5 cm wide, erect, nodding, or pendent; cauline nodes occasionally with short hairs. > 48
48 Glume bodies (6)9-14(19) mm long; lemmas 8-16 mm long, awns usually straight to flexuous; auricles usually present, to 2.5 mm long Elymus glaucus
48 Glume bodies (4.5)6-10(11) mm long; lemmas 5-14 mm long, awns flexuous to moderately outcurving; auricles often absent, or to 1.5 mm long. > 49
49 Lemmas with hairs, the marginal hairs markedly longer than those elsewhere; paleas acute; spikes nodding to pendent; rachis internodes 3-12 mm long; leaves usually deep green; plants native to the Pacific coastal mountains Elymus hirsutus
49 Lemmas smooth, scabrous, or hispid, the marginal hairs, if present, not markedly longer than those elsewhere; paleas obtuse or truncate; spikes erect to slightly nodding; rachis internodes 3-6 mm long; leaves usually pale green, sometimes glaucous; plants introduced Elymus dahuricus
... more about "Elymus"
Mary E. Barkworth +, Julian J.N. Campbell +  and Bjorn Salomon +
Idaho +, Mont. +, Nebr. +, N.C. +, Conn. +, N.J. +, N.Y. +, Mass. +, Wash. +, Va. +, W.Va. +, Ark. +, Iowa +, Kans. +, Mo. +, N.Dak. +, Okla. +, S.Dak. +, Ariz. +, D.C +, Ga. +, Ill. +, Ky. +, Mich. +, N.Mex. +, Pa. +, S.C. +, Tenn. +, Wyo. +, Del. +, Miss. +, Ind. +, Oreg. +, Maine +, N.H. +, R.I. +, Vt. +, Ala. +, Fla. +, La. +, Md. +, N.S. +, Ohio +, Tex. +, Wis. +, Colo. +, Calif. +, Alaska +, Utah +, Nev. +, Alta. +, B.C. +, Greenland +, Man. +, N.B. +, Nfld. and Labr. +, N.W.T. +, Nunavut +, Ont. +, P.E.I. +, Que. +, Sask. +, Yukon +  and Minn. +
barkworth1997a +, barkworth2000a +, barkworth2005a +, bennett2006a +, bodvarsdottir2003a +, booher1948a +, bowden1958a +, bowden1964a +, bowden1967a +, brooks1974a +, brown1960a +, bush1926a +, campbell2000a +, campbell2002a +, campbell2002b +, church1954a +, church1958a +, church1967a +, church1967b +, davies1980a +, dewey1963a +, dewey1965a +, dewey1967a +, dewey1967b +, dewey1968a +, dewey1970a +, dewey1974a +, dewey1975a +, dewey1976a +, dewey1982a +, gabel1984a +, gillett1960a +, gillett1961a +, godley1947a +, hitchcock1935a +, hitchcock1951a +, hitchcock1969d +, hulten1968a +, jensen-a +, jensen1993a +, jones1988b +, jozwik1966a +, lepage1952a +, lepage1965a +, love1984a +, mason-gamer2001a +, nelson1978a +, pohl1959a +, pohl1966a +, porsild1980a +, pyrah1983a +, salomon1991a +, sanders1979a +, smith1991a +, snyder1950a +, snyder1951a +, stebbins1956a +, stebbins1957a +, steyermark1963b +, sun1998a +, sun2003a +, sun2006a +, svitashev1998a +, tsvelev1976a +, vilkomerson1950a +, wilson1963a +, wilson2001a +, yen2005b +  and zhang2002b +
Gramineae +
Poaceae tribe Triticeae +