Elymus curvatus
Elymus ×hansenii
awnless wild-rye, awnless wlldrye, beardless wild rye
Hansen squirreltail, Hansen's wheatgrass, Hansen's wildrye
60-110 cm, stiffly erect, or the base sometimes geniculate;
nodes 6-9, concealed or exposed, glabrous.
60-120 cm.
evenly distributed;
sheaths glabrous, often reddish brown;
auricles to 1 mm, sometimes absent;
ligules shorter than 1 mm, ciliolate;
blades 5-15 mm wide, the lower blades usually lax, shorter, narrower, and senescing earlier, the upper blades usually ascending and somewhat involute, adaxial surfaces smooth or scabridulous, occasionally scabrous.
evenly distributed;
sheaths smooth;
ligules to 1 mm;
blades 10-30 cm long, 2-8 mm wide, flat or the margins involute.
9-15 cm long, (0.5)0.7-1.3 cm wide, erect, exserted or the bases slightly sheathed, with 2 spikelets per node;
internodes 2.5-4.5 mm long, about 0.25-5 mm thick at the thinnest sections, smooth or scabrous beneath the spikelets.
5-20 cm, straight or nodding, with 2+ spikelets per node;
internodes about 10 mm;
disarticulation in the rachises.
10-15 mm, appressed, often reddish brown at maturity, with (2)3-4(5) florets, lowest florets functional;
disarticulation below the glumes and beneath the florets, or the lowest floret falling with the glumes.
about 15 mm, with 3-5 florets.
equal or subequal, the basal 2-3 mm terete, indurate, strongly bowed out, without evident venation, glume bodies 7-15 mm long, 1.2-2.1 mm wide, linear-lanceolate, widening above the base, 3-5-veined, usually glabrous or scabrous, occasionally hispidulous, rarely hirsute on the veins, margins firm, awns 0-3(5) mm;
lemmas 6-10 mm, glabrous or scabrous, rarely hirsute, awns (0.5)1-3(4) mm, rarely 5-10 mm on the lemmas of the distal spikelets, straight;
paleas 6-10 mm, obtuse, often emarginate;
anthers 1.5-3 mm.
narrowly lanceolate, 2-3-veined, awned, awns 25-35 mm;
lemmas 10-12 mm, awned, awns 40-50 mm, outcurving;
paleas subequal to the lemmas, truncate or bidentate.
late June to mid-August.
= 28, 42.
Elymus curvatus
Elymus ×hansenii
Elymus curvatus grows in moist or damp soils of open forests, thickets, grasslands, ditches, and disturbed ground, especially on bottomland. It is widespread from British Columbia and Washington, through the Intermountain region and northern Rockies, to the northern Great Plains. It is infrequent or rare in the midwest, the Great Lakes region, and the northeast, and is virtually unknown in the southeast. It is similar to E. virginicus (p. 298), and has sometimes been included in that species as E. virginicus var. submuticus Hook., but is more distinct than the varieties of E. virginicus treated above. Although E. virginicus and E. curvatus overlap greatly in range, E. curvatus usually has a distinct growth form, and its anthesis is 1-2 weeks later (Brooks 1974). Its spikes range from being completely exserted, especially west of the Great Plains, to largely sheathed, especially east of the Mississippi River and in more stressed environments. This geographic trend parallels that within E. virginicus, but sheathed plants of E. curvatus can usually be distinguished by their short awns. Clear transitions to E. virginicus, usually var. jejunus, are rare, but, especially from Missouri to Wisconsin, there are occasional plants with 5-10 mm awns on a few lemmas, especially at the spike tips. Rarely, plants from Missouri and Iowa to Quebec have hispid to hirsute spikelets, suggesting introgression with E. virginicus var. intermedius. There are a few records of apparent hybrids with other species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Elymus ×hansenii refers to hybrids between E. glaucus (p. 306) and either E. elymoides or E. multisetus (p. 318). It is not clear which of the latter two species is involved. It is a fairly common hybrid in those parts of western North America where both parents grow. The glumes of the type specimen are as wide as those in E. glaucus, and some are divided longitudinally, as in E. elymoides and E. multisetus. As in other hybrids involving E. elymoides and E. multisetus, the rachis of E. ×hansenii disarticulates at maturity.
Elymus ×hansenii 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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