Elymus lanceolatus
Elymus interruptus
streambank wheatgrass, streamside wild rye, thick-spike wildrye, thickspike wheatgrass
Southwestern wildrye
22-130 cm, erect;
nodes glabrous.
usually (40)60-100(120) cm, erect or the bases somewhat decumbent;
nodes 4-8, usually exposed, glabrous.
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 usually glabrous, occasionally hirsute;
auricles 0-2 mm, pale or reddish brown;
ligules to 1 mm;
blades 3-9 mm wide, lax, pale green, adaxial surfaces densely short-pilose, hispidulous, or scabridulous, especially on the veins.
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.
5-20 cm long, 2-5 cm wide, erect to slightly nodding, with 2 spikelets per node;
internodes (5)8-14 mm long, 0.2-0.3 mm thick at the thinnest sections, without pronounced dorsal angles, often with green lateral bands, glabrous beneath the 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.
(6)9-15(22) mm, somewhat to strongly divergent, with 2-5 florets, lowest florets functional;
disarticulation above the glumes and beneath each floret.
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, 15-30 mm including the weakly differentiated awns, the basal 0-1 mm subterete and indurate, glume bodies, when distinguishable, about 6-10 mm long, (0.2)0.3-0.5(0.7) mm wide, linear-setiform to setaceous, entire, widening or parallel-sided above the base, 1-3-veined, glabrous or scabridulous, margins firm, awns straight or flexuous;
lemmas 7-10 mm, smooth or scabridulous, occasionally hirtellous especially near the margins, awns 15-22 mm, straight to moderately outcurving;
paleas 6-9 mm, obtuse or narrowly truncate, sometimes emarginate;
anthers 2-4.5 mm.
May to July.
= 28.
= 28.
Elymus lanceolatus
Elymus interruptus
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 interruptus grows in dry to moist, rocky soil, often in canyons, open woods, and thickets, in the southwestern United States and northern Mexico. Apparent intermediates between E. interruptus and E. canadensis (p. 303) have been collected north of the documented range of typical E. interruptus in Arizona, New Mexico, and Iowa. Plants in the Ozark and Ouachita mountains, especially in Arkansas, that were previously referred to E. interruptus are now included in E. churchii (p. 314).
Elymus interruptus is a poorly understood southern species that, at one extreme, used to be included in E. canadensis or, at the other extreme, used to include E. churchii, E. svensonii (p. 314), and E. diversiglumis (p. 316), three species that seem more closely allied to E. hystrix (p. 316). Campbell (2002) suggested E. interruptus may have arisen from the introgression of E. hystrix or a related species into E. canadensis var. brachystachys. Artificial crosses between E. hystrix and E. canadensis were generally unsuccessful, but yielded some plants resembling E. interruptus (Church 1954). Elymus interruptus has been crossed with E. canadensis, E. hystrix, E. svensonii, E. virginicus (p. 298), E. glabriflorus (p. 296) and E. diversiglumis; only the hybrids with E. diversiglumis were completely sterile (Church 1954, 1967a; Brown and Pratt 1960).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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 |
BC
OR
WA
CalFlora
Flora NW
IL Wildflowers
MI Flora
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
