Plants perennial; synoecious; rhizomatous, rhizomes short or elongate. Culms 50-250 cm, solitary or few. Leaves cauline; sheaths open; ligules of hairs, dense, short; blades elongate, long tapering. Inflorescences terminal, simple panicles, usually exserted and exceeding the upper leaves, open to contracted; panicles 8-80 cm long, to 60 cm wide, simple, flexible, branches not spikelike, not disarticulating. Spikelets with 1 floret, laterally compressed, unawned; rachillas not prolonged; disarticulation above the glumes, achenes falling with the lemmas and paleas. Glumes subequal to unequal, 1-veined, acute; calluses evidently hairy, hairs 1/4 - 7/8 as long as the lemmas; lemmas similar to the glumes, from shorter than to longer than the upper glumes, 1-veined, acute, unawned; paleas longitudinally grooved; anthers 3, 2.4-5.5 mm; ovaries glabrous. Fruit an achene, pericarp free from the seed, x = 10.
Distribution
Ill., Ind., Wash., Alta., B.C., Man., Ont., Sask., Wis., Fla., Wyo., N.J., N.Mex., Tex., N.Y., Nebr., Tenn., N.C., S.C., Pa., Va., Colo., Ala., Kans., N.Dak., Okla., S.Dak., Ark., Iowa, Ariz., Idaho, Ohio, Utah, Mo., Minn., Mich., Mont., Ky.
Discussion
Calamovilfa is a genus of five species, all of which are endemic to temperate portions of the Flora region.
Selected References
Lower Taxa
Key
| 1 | Rhizomes elongate; ligules 0.7-2.5 mm (sect. Interior). | > 2 |
| 2 | Lemmas or paleas (or both) pubescent, although sometimes sparsely so; spikelets 7-10.8 mm long | Calamovilfa gigantea |
| 2 | Lemmas and paleas glabrous; spikelets 5-8.5 mm long | Calamovilfa longifolia |
| 1 | Rhizomes short; ligules to 0.7 mm (sect. Calamovilfa). | > 2 |
| 3 | Panicles contracted, to 3.5 cm wide | Calamovilfa curtissii |
| 3 | Panicles open, 4-40 cm wide. | > 4 |
| 4 | Spikelets 6-7.4 mm; glumes acute to acuminate, usually arcuate; lemmas 5.5-7 mm, arcuate, attenuate | Calamovilfa arcuata |
| 4 | Spikelets 4-5.8 mm; glumes acute, straight; lemmas 4-5.4 mm, straight, acuminate | Calamovilfa brevipilis |