Agrostis idahoensis

Nash
Common names: Idaho redtop
Synonyms: Agrostis filiculmis Agrostis tenuis Vasey
Treatment appears in FNA Volume 24. Treatment on page 649.
Please click on the illustration for a higher resolution version.
Illustrator: Sandy Long

Copyright: Utah State University

Plants perennial; cespitose, not rhizomatous or stoloniferous. Culms 8-40 cm, slender, erect, with 2-5 nodes. Leaves mostly basal; sheaths usually smooth, sometimes scabridulous, not inflated; ligules (0.7) 1-3.8 mm, dorsal surfaces scabridulous, apices rounded to truncate, rarely acute, erose to lacerate; blades 1-7 cm long, 0.5-2 mm wide, flat, becoming involute. Panicles 3-13 cm long, 1-6 (8) cm wide, lanceolate to ovate, diffuse, exserted from the upper sheaths at maturity, lowest node with 1-6 (10) branches; branches scabridulous, fairly stiff, more or less ascending, branching at or above midlength, spikelets not crowded, frequently solitary, lower branches 1-4 cm; pedicels 0.5-6.4 mm. Spikelets lanceolate to narrowly ovate, purplish. Glumes subequal, 1.5-2.5 mm, 1-veined, usually scabrous to scabridulous, upper glumes sometimes smooth, apices acute to acuminate; callus hairs to 0.3 mm, sparse; lemmas 1.2-2.2 mm, usually smooth, sometimes scabridulous, translucent to opaque, 5-veined, veins usually prominent at least distally, sometimes obscure, apices acute to obtuse, entire, unawned; paleas absent, or to 0.2 mm and thin; anthers 3, 0.3-0.6 mm. Caryopses 1-1.3 mm. 2n = 28.

Distribution

Colo., N.Mex., Wash., B.C., Utah, Alaska, Idaho, Mont., Wyo., Ariz., Calif., Nev., Oreg.

Discussion

Agrostis idahoensis grows in western North America, from British Columbia to California and New Mexico, in alpine and subalpine meadows along wet seepage areas and bogs, and in wet openings with Sphagnum in coniferous forests. It was recently discovered in Chile and Argentina; it is not known whether it is native or introduced there (Rugolo de Agrasar and Molina 1997). Agrostis idahoensis is often confused with A. mertensii (p. 644) and dwarf forms of A. scabra (p. 646), both of which tend to grow in better-drained habitats.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Agrostis idahoensis"
membranous +  and scarious +
not penicillate +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.06 cm0.6 mm <br />6.0e-4 m <br />) +
Acute (?) +  and Obtuse (?) +
M.J. Harvey +
1 (?) +  and 3 (?) +
straight +
basal +  and terminal +
geniculate +
rounded +  and keeled +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
1 cm10 mm <br />0.01 m <br /> (7 cm70 mm <br />0.07 m <br />) +
not evident +
scabridulous +
cross +, linear +  and narrowly lanceolate +
0.5mm;2mm +
scabridulous +
spikelike +
0 cm0 mm <br />0 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
hairy +  and glabrous +
Idaho redtop +
not branching +
slender +
8 cm80 mm <br />0.08 m <br /> (40 cm400 mm <br />0.4 m <br />) +
not woody +
Colo. +, N.Mex. +, Wash. +, B.C. +, Utah +, Alaska +, Idaho +, Mont. +, Wyo. +, Ariz. +, Calif. +, Nev. +  and Oreg. +
1/4 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
sterile +  and bisexual +
compressed +
reduced +
(1)1.3-2(4) times longer than +
subtending +
usually scabrous +  and scabridulous +
subequal +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
uncinate +
diffuse +  and dense +
translucent +  and opaque +
pubescent +  and glabrous +
scabridulous +
lanceolate +  and ovate +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
membranous +
0.1 cm1 mm <br />0.001 m <br /> (0.38 cm3.8 mm <br />0.0038 m <br />) +
membranous +
inconspicuous +
lanceolate +
1 cm10 mm <br />0.01 m <br /> (4 cm40 mm <br />0.04 m <br />) +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
concealed +  and prominent +
2 +  and 5 +
2 +  and 1 +
well-developed +
2-keeled +
minute +  and subequal +
0 cm0 mm <br />0 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
3cm +  and 13cm +
lanceolate +  and ovate +
1 cm10 mm <br />0.01 m <br /> (6 cm60 mm <br />0.06 m <br />) +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.64 cm6.4 mm <br />0.0064 m <br />) +
dry +  and fleshy +
not prolonged +
hairy +  and glabrous +
scabridulous +
not inflated +
1 +  and 60 +
lanceolate +  and narrowly ovate +
0.12 cm1.2 mm <br />0.0012 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Agrostis filiculmis +  and Agrostis tenuis +
Agrostis idahoensis +
Agrostis +
species +
membranous +
2 +  and 5 +
not convergent +
obscure +  and prominent +
scabrous +  and scabridulous +
stoloniferous +  and not rhizomatous +
plant +  and cespitose +
aquatic +  and terrestrial +