Flora of North America species comparison

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Elymus multisetus

Elymus ×hansenii

big squirreltail, big squirreltail grass

Hansen squirreltail, Hansen's wheatgrass, Hansen's wildrye
Habit Plants cespitose, not rhizomatous. Plants cespitose, not rhizomatous.
Culms

15-65 cm, erect to ascending, usually puberulent;

nodes 4-6, mostly concealed, glabrous.

60-120 cm.
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.

evenly distributed;

sheaths smooth;

ligules to 1 mm;

blades 10-30 cm long, 2-8 mm wide, flat or the margins involute.
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.

5-20 cm, straight or nodding, with 2+ spikelets per node;

internodes about 10 mm;

disarticulation in the rachises.
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.

about 15 mm, with 3-5 florets.
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.

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.
Anthesis

from late May to June.

2n

= 28.

Elymus multisetus

Elymus ×hansenii
Distribution
from FNA
AZ; CA; CO; ID; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; CO; ID; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
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.)

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.)
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
E. alaskanus, E. albicans, E. arizonicus, E. bakeri, E. canadensis, E. caninus, E. churchii, E. ciliaris, E. curvatus, E. dahuricus, E. diversiglumis, E. elymoides, E. glabriflorus, E. glaucus, E. hirsutus, E. hoffmannii, E. hystrix, E. interruptus, E. lanceolatus, E. macgregorii, E. macrourus, E. pringlei, E. repens, E. riparius, E. scribneri, E. semicostatus, E. sibiricus, E. sierrae, E. stebbinsii, E. svensonii, E. texensis, E. trachycaulus, E. tsukushiensis, E. villosus, E. violaceus, E. virginicus, E. wawawaiensis, E. wiegandii, E. ×cayouetteorum, E. ×ebingeri, E. ×hansenii, E. ×palmerensis, E. ×pinalenoensis, E. ×pseudorepens, E. ×saundersii, E. ×yukonensis
E. alaskanus, E. albicans, E. arizonicus, E. bakeri, E. canadensis, E. caninus, E. churchii, E. ciliaris, E. curvatus, E. dahuricus, E. diversiglumis, E. elymoides, E. glabriflorus, E. glaucus, E. hirsutus, E. hoffmannii, E. hystrix, E. interruptus, E. lanceolatus, E. macgregorii, E. macrourus, E. multisetus, E. pringlei, E. repens, E. riparius, E. scribneri, E. semicostatus, E. sibiricus, E. sierrae, E. stebbinsii, E. svensonii, E. texensis, E. trachycaulus, E. tsukushiensis, E. villosus, E. violaceus, E. virginicus, E. wawawaiensis, E. wiegandii, E. ×cayouetteorum, E. ×ebingeri, E. ×palmerensis, E. ×pinalenoensis, E. ×pseudorepens, E. ×saundersii, E. ×yukonensis
Synonyms Sitanion hansenii
Name authority (J.G. Sm.) Burtt Davy Scribn.
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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