Calamagrostis scopulorum

M.E. Jones
Common names: Jones' reedgrass Ditch reedgrass
Endemic
Treatment appears in FNA Volume 24. Treatment on page 717.

Plants without sterile culms; loosely cespitose, with rhizomes to 2 cm long, 2-3 mm thick. Culms (40)50-92 cm, sometimes branched, sparsely to densely scabrous; nodes 2-3. Sheaths and collars smooth or scabrous; ligules (3)4-7(9) mm, obtuse, lacerate; blades 10-38 cm long, (2)3-4(7) mm wide, flat, scabridulous, adaxial surfaces glabrous or sparsely hairy. Panicles (4)7-16(18) cm long, (0.7)1.1-2(3) cm wide, nodding, contracted, pale green to purple-tinged; branches 1-5(6.5) cm, sparsely to densely scabrous, usually spikelet-bearing to the base. Spikelets (4)4.5-6 mm; rachilla prolongations 1-2 mm, hairy throughout, hairs 1.5-2.5 mm. Glumes keeled, mostly smooth, keels slightly scabrous distally, lateral veins obscure, apices acuminate; callus hairs 2-3 mm, 0.5-0.6 times as long as the lemmas, somewhat sparse; lemmas 3.5-5 mm, 0.5-1.5 mm shorter than the glumes; awns (0.5)1-1.5(2) mm, attached to the upper 2/5 of the lemmas, not exserted, slender, straight, easily overlooked when short; anthers (1.8)2-2.7(3) mm. 2n = 28.

Distribution

Colo., N.Mex., Utah, Mont., Ariz., Wyo.

Discussion

Calamagrostis scopulorum grows on canyon slopes and wash bottoms, and in dry to moist montane to alpine habitats, often on rocky, sandy to silty soil, at 1000-3550 m. It grows from western Montana and Wyoming south to Arizona and New Mexico.

Selected References

None.

Lower Taxa

None.