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streambank wheatgrass, streamside wild rye, thick-spike wildrye, thickspike wheatgrass

Parish wheatgrass, Stebbins' wheat grass, Stebbins' wildrye

Habit Plants strongly rhizomatous, sometimes glaucous. Plants cespitose or shortly rhizomatous.
Culms

22-130 cm, erect;

nodes glabrous.

60-140 cm;

nodes glabrous or retrorsely pubescent.

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 glabrous or pubescent;

auricles usually present, 0.5-2 mm;

ligules 0.3-3.5 mm, truncate to acute, sometimes long-ciliate;

blades 4-6.5 mm wide, flat or the margins involute, straight.

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.

15-31 cm long, 0.4-1.5 cm wide including the awns, 0.4-0.8 cm wide excluding the awns, erect, with 1 spikelet per node;

internodes 9-27 mm long, 1-1.3 mm wide, glabrous, smooth.

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.

13-29 mm long, from shorter than to almost twice as long as the internodes, 2.5-5 mm wide, appressed, with 5-7 florets;

rachillas glabrous;

disarticulation above the glumes and beneath each floret.

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.

subequal, 7.5-12 mm long, 1.2-1.5 mm wide, lanceolate, widest at about mid-length, flat or rounded on the back, 5-veined, veins smooth, scabrous or just the midvein scabridulous, margins widest at about midlength, apices acute, unawned;

lemmas 9-12 mm, glabrous, sometimes scabrous, acute, unawned or awned, awns to 28 mm, straight;

paleas subequal to the lemmas, tapering, apices 0.2-0.3 mm wide;

anthers (3.5)4-7 mm.

2n

= 28.

= 28.

Elymus lanceolatus

Elymus stebbinsii

Distribution
from FNA
AK; AZ; CA; CO; ID; IL; MI; MT; ND; NE; NM; NV; OR; SD; WA; WI; WY; AB; BC; MB; ON; SK; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
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 stebbinsii is restricted to California, where it grows on dry slopes, chaparral, and wooded areas, at elevations below 1600 m. It differs from other Elymus species primarily in its combination of long anthers and solitary spikelets. It is often confused with E. glaucus (p. 306) and E. trachycaulus (p. 321) with solitary spikelets. It differs from both in its longer anthers, and from most representatives of E. glaucus in its acute, but unawned, glumes.

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

Key
1. Lemmas densely hairy, hairs flexible, some 1 mm long or longer
subsp. psammophilus
1. Lemmas glabrous or with stiff hairs shorter than 1 mm.
→ 2
2. Lemmas with hairs, not scabrous
subsp. lanceolatus
2. Lemmas smooth, sometimes scabrous distally, mosdy glabrous, sometimes the lemma margins hairy proximally
subsp. riparius
1. Lemmas awned, awns 8-28 mm long; lower leaf sheaths rarely pubescent; spikelets 13-22 mm long
subsp. septentrionalis
1. Lemmas unawned or with awns to 8(12) mm long; lower leaf sheaths pubescent or glabrous; spikelets 17-29 mm long
subsp. stebbinsii
Source FNA vol. 24, p. 327. FNA vol. 24, p. 329.
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. 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. ×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. 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
Subordinate taxa
E. lanceolatus subsp. lanceolatus, E. lanceolatus subsp. psammophilus, E. lanceolatus subsp. riparius
E. stebbinsii subsp. septentrionalis, E. stebbinsii subsp. stebbinsii
Synonyms Agropyron dasystachyum var. riparium, Agropyron dasystachyum Agropyron parishii
Name authority (Scribn. & J.G. Sm.) Gould Gould
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