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big squirreltail, big squirreltail grass

svenson's wildrye, Syenson's wildrye

Habit Plants cespitose, not rhizomatous. Plants cespitose, not rhizomatous, strongly glaucous.
Culms

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

nodes 4-6, mostly concealed, glabrous.

50-110 cm, erect;

nodes 6-8, mostly exposed, often reddish brown, glabrous.

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 glabrous or villous, often somewhat purplish;

auricles 1-2 mm, purplish or reddish brown;

ligules to 1 mm, often reddish brown;

blades 4-8(10) mm wide, lax, usually pale green, adaxial surfaces usually villous.

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.

10-16 cm long, 3-5 cm wide, nodding, with 2 spikelets per node;

internodes (4)6-10(12) mm long, about 0.2 mm thick at the thinnest sections, flexuous, glabrous, without green lateral bands.

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.

10-16 mm, usually appressed, with (3)4-5 florets, lowest florets functional;

disarticulation above the glumes, beneath each floret.

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.

usually differing in length by more than 5 mm, sometimes vestigial to absent from the upper spikelets or throughout, (0)1-15(18) mm long including the undifferentiated awns, indurate at the base, 0.1-0.3 mm wide, setaceous to subulate, entire, 0-1-veined, tapering from the base, glabrous, margins firm, awns often curving outward;

lemmas 8-10 mm, glabrous, veins occasionally hispidulous near the lemma apices, awns (8)10-20(25) mm, moderately to strongly outcurving at maturity;

paleas 7-9 mm, obtuse or truncate, occasionally emarginate;

anthers 3-5 mm.

Anthesis

from late May to June.

from mid-June to early July.

2n

= 28.

= unknown.

Elymus multisetus

Elymus svensonii

Distribution
from FNA
AZ; CA; CO; ID; NV; OR; UT; WA; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
AR; KY; MO; OK; TN
[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 svensonii grows in dry, rocky soils in open woods of the interior low plateaus, mostly along bluffs of the Kentucky River and its tributaries in the bluegrass region of Kentucky, and along bluffs of the Cumberland River and its Caney Fork in the central basin of Tennessee. Most sites are on Ordovician limestone, but its discovery by Natural Heritage programs in Kentucky along the Green River on Mississippian limestone, and in Tennessee along the Piney River on Silurian limestone, suggest that it may be more widespread. It has been a candidate for federal protection in the United States.

Elymus svensonii, like E. diversiglumis (p. 316) and E. cburchii (see next), may be derived from hybrids between E. hystrix (p. 316) and E. canadensis (p. 303) (Church 1967a), even though E. canadensis currently has its eastern limit 50-100 miles west of most E. svensonii.

Elymus svensonii hybridizes naturally with E. hystrix, E. virginicus (p. 298) and other species of Elymus. Plants with little glume development are frequent; they appear to be introgressed by E. hystrix. Artificial crosses with E. interruptus (p. 306) have been successful, but those with E. diversiglumis have not (Church 1967a). Elymus svensonii resembles E. churchii; it differs in having less open spikes, shorter awns, more florets per spikelet, and more pubescent, glaucous foliage.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 24, p. 318. FNA vol. 24, p. 314.
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. 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
Name authority (J.G. Sm.) Burtt Davy G.L. Church
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