Calamagrostis tweedyi

(Scribn.) Scribn.
Common names: Cascade reedgrass Tweedy's reedgrass
Endemic
Treatment appears in FNA Volume 24. Treatment on page 714.

Plants without sterile culms; loosely cespitose, with rhizomes 1-10 cm long, 2-4 mm thick. Culms (47) 60-120 (150) cm, unbranched, smooth, rarely slightly scabrous; nodes 2-3. Sheaths and collars smooth; ligules (1) 3.5-6 (8) mm, obtuse, lacerate; blades (3) 4-20 (38) cm long, (2) 3-8 (13) mm wide, culm blades wider than 6 mm, flat, abaxial surfaces smooth, adaxial surfaces smooth or slightly scabrous, glabrous or sparsely hairy. Panicles 7-16 (19) cm long, (1) 1.5-2 cm wide, erect, usually contracted, sometimes interrupted near the base, pale-purple to purple; branches (0.2) 2.4-6.7 (7.7) cm, smooth, sometimes sparsely scabrous distally, spikelet-bearing to the base. Spikelets (4.5) 5.5-8 (9) mm; rachilla prolongations (0.5) 1-2 (4) mm, hairs 1.5-3 mm. Glumes keeled, smooth or the keels scabrous, lateral-veins prominent, apices acute; callus hairs 0.8-1 mm, 0.2-0.3 times as long as the lemmas, sparse; lemmas (4) 4.5-6.5 (7.5) mm, 0-1.5 mm shorter than the glumes, scabridulous; awns 6-8 mm, attached to the lower 1/5 – 3/10 of the lemmas, exserted more than 2 mm, stout, easily distinguished from the callus hairs, bent; anthers 2-3.5 mm. 2n = unknown.

Discussion

Calamagrostis tweedyi grows in montane to subalpine moist meadows and coniferous forests, often in association with Carex geyeri, at 900-2000 m. Its range extends from Washington and Oregon to western Montana.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Calamagrostis tweedyi"
membranous +  and scarious +
hairy +, glabrous +, scabrous +  and smooth +
0.2 cm2 mm <br />0.002 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
Kendrick L. Marr +, Richard J. Hebda +  and Craig W. Greenef +
(Scribn.) Scribn. +
1 (?) +  and 3 (?) +
straight +
attached +
exserted +  and lower +
distinguished +
1/5 +  and 3/10 +
0.6 cm6 mm <br />0.006 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
4 cm40 mm <br />0.04 m <br /> (20 cm200 mm <br />0.2 m <br />) +
not evident +
flat +  and involute +
3mm;8mm +
0.2 cm2 mm <br />0.002 m <br /> (?) +
appressed;more or less drooping +
spikelike +
0.2-0.3 times as long as the lemmas +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
Cascade reedgrass +  and Tweedy's reedgrass +
ascending +  and erect +
60 cm600 mm <br />0.6 m <br /> (120 cm1,200 mm <br />1.2 m <br />) +
not woody +
Mont. +, Idaho +  and Wash. +
1/4 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sometimes longer +
sterile +  and bisexual +
compressed +
reduced +
subtending +
subequal +
membranous +
sparse +  and abundant +
uncinate +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
scabridulous +
lanceolate +  and ovate +
0 cm0 mm <br />0 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
lacerate +  and obtuse +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
membranous +
inconspicuous +
lanceolate +
concealed +  and prominent +
2 +  and 3 +
2 +  and 1 +
hairy +  and glabrous +
2-keeled +
pale-purple +  and purple +
7cm +  and 16cm +
spikelike +
1.5 cm15 mm <br />0.015 m <br /> (2 cm20 mm <br />0.02 m <br />) +
dry +  and fleshy +
1 +  and 60 +
compressed +
0.55 cm5.5 mm <br />0.0055 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Gramineae +
Calamagrostis tweedyi +
Calamagrostis +
species +
membranous +
parallel +  and converging +
obscure +  and prominent +
plant +  and cespitose +
aquatic +  and terrestrial +