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

Arizona ryegrass, Arizona wheatgrass, Arizona wildrye

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

22-130 cm, erect;

nodes glabrous.

45-100 cm, erect or decumbent at the base;

nodes glabrous or almost so.

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 over the lower 1/2 of the culms;

sheaths glabrous;

auricles usually present, to 1 mm;

ligules to 1 mm on the basal leaves, 1-3 mm on the flag leaves;

blades 2.5-6 mm wide, lax, abaxial surfaces smooth and glabrous, adaxial surfaces scabrous, with scattered 0.5-1 mm hairs, veins close together.

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.

12-25 cm long, 2.5-6 cm wide including the awns, 10-15 mm wide excluding the awns, flexuous, usually nodding or pendent at maturity, with 1 spikelet per node;

internodes 11-17 mm long, 0.4-1 mm wide, glabrous, mostly smooth, scabrous on the edges.

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.

14-26 mm long, 6-8 mm wide, appressed to divergent, 1.5-2 times as long as the internodes, with 4-6 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.

narrowly lanceolate, margins about 0.2 mm wide, 3(5)-veined, the bases flat, evidently veined, margins hyaline, widest at about midlength, acute or acuminate, unawned or awned, awns to 4 mm, straight;

lower glumes 5-9 mm;

upper glumes 8-10 mm;

lemmas 8-15 mm, scabrous, rounded on the back, awns 10-25 mm, arcuately diverging;

paleas as long as or longer than the lemmas, tapering, apices truncate, about 0.3 mm wide;

anthers 3-5 mm.

2n

= 28.

= 28.

Elymus lanceolatus

Elymus arizonicus

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
AZ; CA; NM; TX
[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 arizonicus grows in moist, rocky soil in mountain canyons of the southwestern United States and northern Mexico. When mature, the drooping spike and solitary spikelets make E. arizonicus easy to identify. Immature specimens, or those mounted so that the spike appears erect, are easily mistaken for Pseudoroegneria spicata (p. 281), but they have thicker culms and longer ligules, more basal leaves, and wider leaf blades.

(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
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. 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. ×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
Synonyms Agropyron dasystachyum var. riparium, Agropyron dasystachyum Pseudoroegneria arizonica, Agropyron arizonicum
Name authority (Scribn. & J.G. Sm.) Gould (Scribn. & J.G. Sm.) Gould
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