Elymus lanceolatus |
Elymus ×ebingeri |
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streambank wheatgrass, streamside wild rye, thick-spike wildrye, thickspike wheatgrass |
wildrye |
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Habit | Plants strongly rhizomatous, sometimes glaucous. | Plants cespitose, not rhizomatous. | ||||||||
Culms | 22-130 cm, erect; nodes glabrous. |
50-135 cm, usually smooth, glabrous, sometimes retrorsely hairy; nodes glabrous or hairy. |
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Leaves | often mostly basal, sometimes more evenly distributed; sheaths glabrous or pubescent; auricles usually present on the lower leaves, 0.5-1.5 mm; ligules 0.1-0.5 mm, erose, sometimes ciliolate; blades 1.5-6 mm wide, generally involute, abaxial surfaces usually glabrous, adaxial surfaces strigose, ribs subequal in size and spacing. |
evenly distributed; sheaths smooth or scabridulous, hairy; ligules to 1 mm; blades 14-26 cm long, to 12 mm wide, flat, both surfaces scabridulous, adaxial surfaces hairy. |
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Spikes | 3.5-26 cm long, 0.5-1 cm wide, erect to slightly nodding, usually with 1 spikelet per node, sometimes with 2 at a few nodes; internodes 3.5-15 mm long, 0.1-0.8 mm wide, glabrous or hairy. |
8-17 cm, with (1)2+ spikelets per node; internodes 4-8 mm. |
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Spikelets | 8-31 mm, 1.5-3 times longer than the internodes, appressed, with 3-11 florets; rachillas glabrous or hairy, hairs to 1 mm; disarticulation above the glumes, beneath each floret. |
diverging at about 45° from the rachises, not patent. |
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Glumes | subequal, 5-14 mm long, 1/2 - 3/4 the length of the adjacent lemmas, 0.7-1.3 mm wide, lanceolate, glabrous or hairy, smooth or scabrous, 3-5-veined, flat or weakly, often asymmetrically keeled, keels straight, margins narrow, tapering from the base or from beyond midlength, apices acute to acuminate, sometimes mucronate or shortly awned; lemmas 7-12 mm, glabrous or hairy, hairs all alike, sometimes scabrous, acute to awn-tipped, awns to 2 mm, straight; paleas about equal to the lemmas, keels straight below the apices, smooth or scabrous proximally, sometimes hairy, scabrous distally, intercostal region glabrous or with hairs, apices 0.2-0.3 mm wide; anthers (2.5)3-6 mm. |
usually subequal, 15-20 mm, bases indurate, bodies lanceolate to subulate, scabrous, sometimes the lower glumes reduced to a stub; lemmas 8-10 mm, glabrous or strigose, sometimes scabrous, awns 23-29 mm, straight, scabrous; anthers 2-2.9 mm. |
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Caryopses | seldom formed. |
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2n | = 28. |
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Elymus lanceolatus |
Elymus ×ebingeri |
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Distribution |
AK; AZ; CA; CO; ID; IL; MI; MT; ND; NE; NM; NV; OR; SD; WA; WI; WY; AB; BC; MB; ON; SK; YT
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CT; IL; IN; MO; NY; WI; ON |
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Discussion | Elymus lanceolatus grows in sand and clay soils and dry to mesic habitats. It is found primarily in the western half of the Flora region, between the coastal mountains and 95° W longitude, with the exception of E. lanceolatus subsp. psammophilus, which extends around the Great Lakes. Three subspecies are recognized, primarily on the basis of their lemma and palea pubescence. Elymus lanceolatus is primarily outcrossing, and hybridizes with several species of Triticeae. Elymus albicans (p. 334) is thought to be derived from hybridization with the awned phase of Pseudoroegneria spicata (p. 281). Judging from specimens of controlled hybrids, hybridization with E. trachycaulus (p. 321) and unawned plants of P. spicata probably occur, but would be almost impossible to detect without careful observation in the field. Experimental hybrids are partially fertile, and capable of backcrossing to either parent (Dewey 1965, 1967, 1968, 1975, 1976). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Elymus ×ebingeri is the name for hybrids between E. virginicus (p. 298) and E. hystrix (p. 316). It is frequently found where the two parental species grow together, often with later hybrid generations and introgressants to the two parents. It has been reported from southern Ontario, and from Wisconsin to New York and Illinois. Most published reports simply refer to the existence of these hybrids, the name itself not having been published until 1996. Elymus ×ebingeri is an Elymus named hybrid Elymus is notorious for its ability to hybridize. Most of its interspecific hybrids are partially fertile, permitting introgression between the parents. The descriptions provided below are restricted to the named interspecific hybrids. They should be treated with caution and some skepticism; some are based solely on the type specimen, because little other reliably identified material was available. Moreover, as the descriptions of the non-hybrid species indicate, many other interspecific hybrids exist. The parentage of all hybrids is best determined in the field. Perennial hybrids, such as those in Elymus, can persist in an area after one or both parents have died out, but the simplest assumption is that both are present. Interspecific hybrids of Elymus that have disarticulating rachises presumably have E. elymoides or E. multisetus as one of their parents. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 24, p. 327. | FNA vol. 24, p. 343. | ||||||||
Parent taxa | Poaceae > subfam. Pooideae > tribe Triticeae > Elymus | Poaceae > subfam. Pooideae > tribe Triticeae > Elymus | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | Agropyron dasystachyum var. riparium, Agropyron dasystachyum | |||||||||
Name authority | (Scribn. & J.G. Sm.) Gould | G.C. Tucker | ||||||||
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