Elymus wawawaiensis

J.R. Carlson & Barkworth
Common names: Snakeriver wheatgrass
Treatment appears in FNA Volume 24. Treatment on page 332.

Plants cespitose, sometimes weakly rhizomatous. Culms (15) 50-130 cm, erect, mostly glabrous; nodes usually glab¬rous, sometimes slightly pubescent. Leaves more or less evenly distributed; basal sheaths glabrate, margins not evidently ciliate; auricles absent or to 1.2 mm; ligules 0.1-1.1 mm; blades to 28 cm long, 1.7-5 mm wide, involute when dry, adaxial surfaces usually densely pubescent, rarely sparsely pubescent. Spikes 5-20 cm long, 2.5-3 cm wide including the awns, erect to slightly nodding, with 1 spikelet per node; internodes 5-12 mm long, about 0.2 mm thick, about 0.3 mm wide, glabrous beneath the spikelets. Spikelets 10-22 mm long, about twice as long as the internodes, 2-8.5 mm wide, appressed, with 4-10 florets; rachillas glabrous; disarticulation above the glumes, beneath each floret. Glumes 4-10 mm long, 0.5-1.3 mm wide, narrowly lanceolate, widest at or below midlength, glabrous, often glaucous, 1-3-veined, flat or weakly keeled, margins 0.1-0.2 mm wide, widest near midlength, apices usually acuminate, awned or unawned, awns to 6 mm; lemmas 6-12 mm, smooth or slightly scabrous, margins often sparsely pubescent proximally, apices awned, longest awns in the spikelets 9-28 mm, strongly divergent; paleas 7.2-10.5 mm, keels scabrous distally, tapering to the 0.2-0.3 mm wide apices; anthers 3.5-6 mm. 2n = 28.

Discussion

Elymus wawawaiensis grows primarily in shallow, rocky soils of slopes in coulees and reaches of the Salmon, Snake, and Yakima rivers of Washington, northern Oregon, and Idaho. There are also a few records from localities at some distance from the Snake River and its tributaries. These probably reflect deliberate introductions. C.V. Piper, who worked for the U.S. Department of Agriculture in southeastern Washington from 1892-1902, frequently distributed seed to farmers in the region from populations that he considered superior; he considered E. wawawaiensis to be a superior form of what is here called Pseudo-roegneria spicata (p. 281). Another source of introduced populations is 'Secar', a cultivar of E. wawawaiensis that is recommended as a forage grass for arid areas of the northwestern United States.

Elymus wawawaiensis resembles a vigorous version of Pseudoroegneria spicata, and was long confused with that species. It differs in its more imbricate spikelets and narrower, stiff glumes. In its primary range, E. wawawaiensis is often sympatric with P. spicata, but the two tend to grow in different habitats, E. wawawaiensis growing in shallow, rocky soils and P. spicata in medium- to fine-textured loess soil. The two species also differ cytologically, E. wawawaiensis being an allo-tetraploid, and P. spicata consisting of diploids and autotetraploids.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.No values specified.

... more about "Elymus wawawaiensis"
membranous +  and scarious +
with hairs +  and scabrous +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
awned +  and unawned +
acuminate +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
Mary E. Barkworth +, Julian J.N. Campbell +  and Bjorn Salomon +
J.R. Carlson & Barkworth +
1 (?) +  and 3 (?) +
straight +
basal +  and apical +
from the sinus +  and terminal +
not geniculate +
0 cm0 mm <br />0 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
0 cm0 mm <br />0 m <br /> (28 cm280 mm <br />0.28 m <br />) +
not evident +
cross +, linear +  and narrowly lanceolate +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
spikelike +
0 cm0 mm <br />0 m <br /> (1 cm10 mm <br />0.01 m <br />) +
hairy +  and glabrous +
Snakeriver wheatgrass +
not branching +
sometimes strongly decumbent +  and prostrate +
50 cm500 mm <br />0.5 m <br /> (130 cm1,300 mm <br />1.3 m <br />) +
not woody +
Idaho +, Oreg. +  and Wash. +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
4 +  and 10 +
laterally compressed +  and terete +
shorter than to longer than the adjacent florets +
4mm +  and 10mm +
subtending +
glaucous +  and glabrous +
keeled +, flat +  and lanceolate +
unequal +, subequal +  and reduced +
widest +, 0.5mm +  and 1.3mm +
uncinate +
solid +  and hollow +
1.5 cm15 mm <br />0.015 m <br /> (?) +
5mm +  and 12mm +
0.2 cm2 mm <br />0.002 m <br /> (2.6 cm26 mm <br />0.026 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (?) +
0.3 cm3 mm <br />0.003 m <br /> (?) +
ciliate +  and scabrous +
tapering +
distributed +
scabrous +  and smooth +
linear-lanceolate +
0.6 cm6 mm <br />0.006 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
stiffly membranous +  and coriaceous +
erose +  and entire +
acute +, rounded +  and truncate +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.11 cm1.1 mm <br />0.0011 m <br />) +
membranous +
inconspicuous +
lanceolate +
fleshy +  and membranous +
widest;0.1mm;0.2mm +
concealed +  and prominent +
2 +  and 1 +
hairy +  and glabrous +
well-developed +
slightly longer +
subequal +
0.72 cm7.2 mm <br />0.0072 m <br /> (1.05 cm10.5 mm <br />0.0105 m <br />) +
dry +  and fleshy +
spikelike +
5 cm50 mm <br />0.05 m <br /> (?) +  and 20 cm200 mm <br />0.2 m <br /> (?) +
subsessile +  and sessile +
bisexual +  and sterile +
terete +  and compressed +
0.9 cm9 mm <br />0.009 m <br /> (2.8 cm28 mm <br />0.028 m <br />) +
2mm +  and 8.5mm +
1 +  and 3 +
simple +  and compound +
2 (?) +  and 3 (?) +
not papillate +
Gramineae +
Elymus wawawaiensis +
species +
membranous +
0 cm0 mm <br />0 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
inconspicuous +
unequal +
plant +  and cespitose +
aquatic +  and terrestrial +