Elymus lanceolatus |
Elymus villosus |
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streambank wheatgrass, streamside wild rye, thick-spike wildrye, thickspike wheatgrass |
downy wild-rye, hairy wildrye, silky wild rye |
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Habit | Plants strongly rhizomatous, sometimes glaucous. | Plants cespitose, not rhizomatous, often persistently deep green. | ||||||||
Culms | 22-130 cm, erect; nodes glabrous. |
40-130 cm, erect; nodes 4-8, concealed or exposed, glabrous. |
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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 villous-hirsute, pilose, or occasionally glabrate, occasionally reddish brown; auricles 1-3 mm, brownish; ligules shorter than 1 mm, entire or erose; blades 4-12 mm wide, lax, dark glossy green, adaxial surfaces usually densely velutinous-villous with fine whitish hairs, rarely pilose only on the veins. |
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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. |
4-12 cm long, 1.5-3.5 cm wide, slightly or strongly nodding, exserted, usually with 2 spikelets per node, rarely with 1 or 3 at a few nodes; internodes (1.5)2-3(4) mm long, 0.15-0.25 mm thick at the thinnest sections, usually hairy below the spikelets, rarely glabrous. |
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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. |
7-12 mm, moderately divergent, with 1-2(3) florets, lowest florets functional; disarticulation above the glumes and beneath each floret. |
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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. |
equal, 12-25 mm including the often undifferentiated awns, the basal 0.5-2 mm terete, slightly indurate, straight or nearly so, without evident venation, glume bodies 7-10 mm long, (0.2)0.3-0.8 mm wide, linear-setiform, widening or parallel-sided above the base, 2-3(4)-veined, usually hirsute to hispid, occasionally scabrous to scabridulous, margins firm, awns 5-15 mm, straight; lemmas 5.5-9 mm, usually villous with fine, whitish, spreading hairs, especially near the margins and apices, sometimes glabrous or with coarser hairs, sometimes scabrous, awns 9-33 mm, straight; paleas 5-7.5 mm, obtuse, occasionally emarginate; anthers (1.6)2-3(4) mm. |
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Anthesis | early June to early July. |
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2n | = 28. |
= 28. |
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Elymus lanceolatus |
Elymus villosus |
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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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AL; AR; CT; DC; DE; GA; IA; IL; IN; KS; KY; MA; MD; MI; MN; MO; MS; NC; ND; NE; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WI; WV; WY; ON; QC
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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 villosus grows in moist to moderately dry, often rocky soils in woods and thickets, especially in calcareous or other base-rich soils, but it is also frequent on drier, sandy soils or damper, alluvial soils in glaciated regions. It extends from the Great Plains east to southern Quebec, northern New York, and Vermont south to Texas, Georgia, and South Carolina. It is absent from the southern portion of the coastal plain. Elymus villosus is relatively uniform and distinct, although it has sometimes been confused with hairy plants of E. canadensis (p. 303) and E. glabriflorus (p. 296). The hairs of E. villosus are fine, whitish, and consistently dense on the leaf blades, typically spreading in the spikelets; the hairs of the other species are typically stouter and more appressed in the spikelets. Plants called E. villosus var. arkansanas (Scribn. & C.R. Ball) J.J.N. Campb. are scabrous to glabrous in the spikes, except for the ciliate rachis margins, and often more robust. These are scattered over much of the species' range, except in the north (from Wisconsin to New England), and are locally more frequent than typical plants in the Ozark Mountains and other midwestern hills. Some other western plants (including those called E. striatus var. ballii Pammel) have unusually large, almost erect spikes, suggesting introgression from E. virginicus (p. 298). There are rare apparent hybrids with species in the E. virginicus group, but the only proven natural hybrid is with Hordeum fubatum (p. 245) (see *Elyhordeum, p. 283). Artificial crosses with several species failed to produce healthy Fj plants (Church 1958). (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. 302. | ||||||||
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 | E. villosus var. arkansanus, E. arkansanus | ||||||||
Name authority | (Scribn. & J.G. Sm.) Gould | Muhl. ex Willd. | ||||||||
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