Elymus multisetus |
Elymus ×yukonensis |
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big squirreltail, big squirreltail grass |
Yukon wheatgrass |
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Habit | Plants cespitose, not rhizomatous. | Plants rhizomatous. |
Culms | 15-65 cm, erect to ascending, usually puberulent; nodes 4-6, mostly concealed, glabrous. |
about 60 cm, erect. |
Leaves | evenly distributed; sheaths glabrous or white-villous; auricles usually present, 0.5-1.5 mm; ligules to 1 mm, truncate, entire or lacerate; blades 1.5-4(5) mm wide, often ascending and involute, adaxial surfaces scabrous, pilose, or villous. |
somewhat basally concentrated; blades 3.5-6 mm wide. |
Spikes | 5-20 cm long, 5-15 cm wide, erect, sometimes partially enclosed at the base, with 2 spikelets per node, rarely with 3-4 at some nodes; internodes 3-5(8) mm long, 0.1-0.3 mm thick at the thinnest sections, glabrous beneath the spikelets. |
6-10 cm long, 0.7-1.7 cm wide, with 1 spikelet per node; internodes 6-11 mm. |
Spikelets | 10-15 mm, divergent, with 2-4 florets, lowest florets sterile and glumelike in 1 or both spikelets at each node; disarticulation initially at the rachis nodes, subsequently beneath each floret. |
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Glumes | subequal, (10)30-100 mm including the awns, the bases indurate and glabrous, glume bodies (2)5-10 mm long, 1-2 mm wide, setaceous, 2-3-veined, margins firm, awns (8)25-90 mm, each split into 3-9 unequal divisions, scabrous, flexuous to outcurving from near the glume bases at maturity; fertile lemmas 8-10 mm, smooth or scabrous near the apices, 2 lateral veins extending into bristles to 10 mm, awns (10)20-110 mm long, about 0.2 mm wide at the base, divergent to arcuate; paleas 7-9 mm, veins usually extending into about 1 mm bristles, apices acute to truncate; anthers 1-2 mm. |
4-5.5 mm, about 1/2 the length of the adjacent lemmas, lanceolate, flat, hairy, apices acute or awn-tipped, awns shorter than 1 mm; rachillas densely hairy; lemmas 6-9 mm, densely villous, unawned; anthers 3.3-3.6 mm. |
Anthesis | from late May to June. |
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2n | = 28. |
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Elymus multisetus |
Elymus ×yukonensis |
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Distribution |
AZ; CA; CO; ID; NV; OR; UT; WA; WY
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AK; BC |
Discussion | Elymus multisetus grows in dry, often rocky, open woods and thickets on slopes and plains, from central Washington and Idaho to southern California, Colorado, and northwestern Arizona, and from sea level to 2000 m. It has also been reported from Baja California, Mexico. It usually grows in less arid habitats than E. elymoides subsp. elymoides (p. 319), but the two taxa are sometimes sympatric. Wilson (1963) reported a wide belt of introgression between Elymus multisetus and E. elymoides subsp. elymoides from southeastern California to southern Nevada, but not in other areas where they are sympatric. There are also probable hybrids with E. glaucus (p. 306) and Pseudoroegneria spicata (p. 281). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The parents of Elymus ×yukonensis have not been identified. Morphological and geographic considerations suggest that they may be E. lanceolatus subsp. psammophilus (p. 327) and E. alaskanus (p. 326). Elymus ×yukonensis 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.) |
Source | FNA vol. 24, p. 318. | FNA vol. 24, p. 340. |
Parent taxa | Poaceae > subfam. Pooideae > tribe Triticeae > Elymus | Poaceae > subfam. Pooideae > tribe Triticeae > Elymus |
Sibling taxa | ||
Synonyms | Agropyron yukonense | |
Name authority | (J.G. Sm.) Burtt Davy | (Scribn. & Merr.) Á. Löve |
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