Elymus alaskanus |
Elymus interruptus |
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Alaska wild rye, alaskan wheatgrass, ellisia |
Southwestern wildrye |
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Habit | Plants cespitose or weakly rhizomatous. | Plants cespitose, not rhizomatous, usually glaucous. | ||||
Culms | 20-90 cm, sometimes decumbent at the base, ascending to erect above; nodes usually pubescent, sometimes glabrous. |
usually (40)60-100(120) cm, erect or the bases somewhat decumbent; nodes 4-8, usually exposed, glabrous. |
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Leaves | sometimes basally concentrated; sheaths smooth or scabrous, glabrous or pilose; auricles absent or to 0.5 mm; ligules 0.2-1 mm, erose, ciliolate; blades 3-7 mm wide, flat, both surfaces smooth, scabrous, or pubescent. |
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. |
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Spikes | 3.5-14 cm long, 0.5-0.8 cm wide, erect or nodding distally, usually with 1 spikelet per node, occasionally with 2 at the lower nodes; internodes 3-10 mm long, 0.5-0.8 mm wide, mostly glabrous and smooth, edges scabrous or ciliate. |
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. |
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Spikelets | 9-15(20) mm, 2-5 times longer than the internodes, appressed, with 3-6 florets, rachillas hispidulous; disarticulation above the glumes, beneath each floret. |
(6)9-15(22) mm, somewhat to strongly divergent, with 2-5 florets, lowest florets functional; disarticulation above the glumes and beneath each floret. |
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Glumes | 4-8 mm long, (1.2)1.5-2 mm wide, 1/3-2/3 as long as the adjacent lemmas, oblanceolate to obovate, flat, usually purplish, glabrous or hairy, hairs 0.3-0.5 mm, margins unequal, the widest margin 0.4-1 mm wide, both margins widest above the middle, apices unawned or awned, awns to 1 mm; lemmas 7-11 mm, glabrous or hairy, sometimes scabridulous, sometimes more densely hairy distally, hairs 0.2-0.6 mm, all alike, apices unawned or awned, awns to 7 mm, straight; paleas subequal to the lemmas, keels straight below the apices; anthers 1-2 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. |
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Anthesis | May to July. |
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2n | = 28. |
= 28. |
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Elymus alaskanus |
Elymus interruptus |
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Distribution |
AK; CO; ID; MI; MT; NM; NV; OR; WA; WY; AB; BC; MB; NF; NS; NT; NU; ON; QC; YT; Greenland |
AZ; CA; NM; TX |
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Discussion | Elymus alaskanus extends across the high arctic of North America to extreme eastern Russia. This treatment interprets E. alaskanus as having relatively short glumes, in accordance with its treatment by Hulten (1968). Large specimens resemble E. macrourus (see previous), but differ in the shape of their glumes and in their wider glume margins. Elymus alaskanus differs from E. trachycaulus (p. 321) in its greater cold tolerance and the distal widening of its glume margins. There is some intergradation, particularly with E. violaceus (p. 324) and E. trachycaulus, but these species have longer glumes. Moreover, in western North America, E. violaceus is restricted to rocky habitats at or above treeline, whereas E. alaskanus is often associated with valleys and flat areas. Reports of its extending to New Mexico are based on the inclusion of high-elevation forms of E. trachycaulus. (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.) |
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Key |
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Source | FNA vol. 24, p. 326. | FNA vol. 24, p. 306. | ||||
Parent taxa | Poaceae > subfam. Pooideae > tribe Triticeae > Elymus | Poaceae > subfam. Pooideae > tribe Triticeae > Elymus | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Roegneria villosa, Roegneria borealis, E. alaskanus subsp. borealis, Agropyron alaskanum | E. canadensis var. interruptus | ||||
Name authority | (Scribn. & Merr.) Á.Löve | Buckley | ||||
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