A. álba, L. (Fiorin or White Bent-Grass.) Rootstocks creeping or stoloniferous; culms 1–2° high, often decumbent at base; leaves short, flat, the ligule long and acute; panicle contracted after flowering, greenish, purplish or brownish, the branches slightly rough; flowering glume nearly equalling the empty ones, 3-nerved, rarely short-awned, the palet about half as long.—Meadows and fields, a valuable grass; naturalized from Eu. and cultivated, and perhaps native north and westward.
Var. vulgàris, Thurb. (Red Top. Herd's-Grass of Penn., etc.) (Pl. 7, fig. 1, 2.) Panicle more or less spreading after flowering; ligule short and truncate. (A. vulgaris, With.)—Low meadows and pastures; nat. from Eu. and cultivated, also perhaps indigenous.
1. A. arachnoìdes, Ell. Culms (1° high) and leaves very slender; panicle open, weak and drooping; glumes nearly equal, roughish on the keel and margins, the flowering glume shorter, with 2 minute bristles at the truncate apex and a long exceedingly delicate awn on the back above the middle; palet minute.—Mo. to Ky., Tenn., and S. Car.
2. A. exaràta, Trin. Culms erect, 1–2° high; leaves mostly erect; panicle narrow, crowded, greenish, the rays mostly flower-bearing to the base; spikelets 1½–2´´ long; glumes nearly equal, acute, the flowering ones shorter, sometimes awned above the middle.—Wisc. (Vasey) to Sask., and far westward.
§ 2. TRICHÒDIUM. Palet abortive, minute, or none.
3. A. elàta, Trin. Culms firm or stout (2–3° high); leaves flat (1–2´´ wide); upper ligules elongated (2–3´´ long); spikelets crowded on the branches of the spreading panicle above the middle (1½´´ long); flowering glume awnless, slightly shorter than the rather unequal lower ones; the palet wanting.—Swamps, N. J. and southward. Oct.
4. A. perénnans, Tuckerm. (Thin-Grass.) Culms slender, erect from a decumbent base (1–2° high); leaves flat (the upper 4–6´ long, 1–2´´ wide); panicle at length diffusely spreading, pale green; the branches short, divided and flower-bearing from or below the middle; flowering glume awnless (rarely short-awned), shorter than the unequal lower ones; the palet minute or obsolete.—Damp shaded places. July, Aug.—Spikelets, etc., as in n. 5, into which it seems to vary.
5. A. scàbra, Willd. (Hair-Grass.) (Pl. 7, fig. 3.) Culms very slender, erect (1–2° high); leaves short and narrow, the lower soon involute (the upper 1–3´ long, less than 1´´ wide); panicle very loose and divergent, purplish, the long capillary branches flower-bearing at and near the apex; flowering glume awnless or occasionally short-awned on the back, shorter than the rather unequal very acute empty ones; the palet minute or obsolete; root biennial?—Exsiccated places; common. June–Aug.—Remarkable for the long and divergent capillary branches of the extremely loose panicle; these are whorled, rough with very minute bristles (under a lens), as also the keel of the glumes. Spikelets 1´´ long. A dwarf mountain form occurs, growing in tufts in hollows of rocks, etc.—A variety (?) from about the White Mountains, etc. (var. montana, Tuckerm.), has a more or less exserted awn.
6. A. canìna, L. (Brown Bent-Grass.) Culms 8´–2° high; root-leaves involute-bristle-form, those of the culm flat and broader; panicle loose; lower glumes slightly unequal, ovate-lanceolate, very acute, the flowering one exsertly awned on the back at or below the middle; spikelets brownish or purplish, rarely pale or greenish (1–1½´´ long).—Meadows, sparingly naturalized eastward. A mountain form with shorter and more spreading panicle (A. Pickeríngii & A. concinna, Tuckerm., A. canina, var. alpina, Oakes, & Ed. 2, and essentially A. rubra, L. ex Wahl., and A. borealis, Hartm.) is indigenous on mountain-tops, Maine to N. Y.; also an ampler form in the Alleghanies of Penn. and southward (A. rupéstris, Chapman, etc.). July–Aug. (Eu.)
30. POLYPÒGON, Desf. Beard-Grass. ([Pl. 8.])