Plants usually perennial, rarely annual; cespitose or rhizomatous, rarely both cespitose and rhizomatous. Culms (8)20-200 cm, glabrous or pubescent; nodes glabrous or retrorsely glabrous or puberulent; blade flat, pubescent. Inflorescences terminal panicles, contracted to open. Spikelets laterally compressed, with 2(3) florets, lower florets bisexual, upper floret(s) staminate or sterile; rachillas curved below the lowest florets, sometimes prolonged beyond the base of the distal florets; disarticulation below the glumes. Glumes equaling to exceeding the florets, strongly keeled, unawned; upper lemmas awned from below the apices, awns hooked or geniculate; paleas thin, subequal to the lemmas; lodicules 2, glabrous, toothed or not; anthers 3; ovaries glabrous. Caryopses shorter than the lemmas, concealed at maturity, glabrous. x = 4, 7.
Distribution
Conn., N.J., N.Y., Del., N.C., Va., D.C, Wis., W.Va., Pacific Islands (Hawaii), Mass., Maine, N.H., R.I., Vt., Wash., Alta., B.C., N.B., Nfld. and Labr. (Labr.), N.S., Ont., Que., Sask., N.Mex., Tex., La., Tenn., S.C., Pa., Okla., Alaska, Nev., Puerto Rico, Colo., Md., Calif., Ala., Ark., Ill., Ga., Ind., Iowa, N.Dak., Ariz., Idaho, Mont., Oreg., Ohio, Utah, Mo., Mich., Kans., Miss., Ky.
Discussion
Holcus, a genus of eight species, is native to Europe, North Africa, and the Middle East. One species, H. lanatus, has become widely naturalized in the Americas, Japan, and Hawaii; a second, H. mollis, has become a troublesome weed in some areas of the Flora region.
Selected References
Lower Taxa
Key
| 1 | Awns 1-2 mm long, forming a curved hook at maturity; culms densely pilose adjacent to the lower nodes; plants cespitose, not rhizomatous | Holcus lanatus |
| 1 | Awns 3-5 mm long, straight or geniculate at maturity; culms glabrous or sparsely pubescent adjacent to the lower nodes; plants not cespitose, rhizomatous | Holcus mollis |