648 GRAMINE^. (grass FAMILY.) 



2. A. exar^ta, Trin. Culms erect, 1-2° high; leaves mostly erect; 

 pauicle narrow, crowded, greeuish, the rays mostly flower-bearing to the base ; 

 spikelets H -2" long; glumes nearly equal, acute, the flowering ones shorter, 

 sometimes awned above the middle. — Wise. {Vasei/) to Sask., and far 

 westward. 



§ 2. TRICHODIUM. Palet abortive, minute, or none, 



3. A. elata, Trin. Culms firm or stout (2 - 3° high) ; leaves flat (1 - 2'' 

 wide) ; upper ligules elongated (2-3" long) ; spikelets crowded on the branchec 

 of the spreading panicle above the middle (\^" long) ; flowering glume awnless, 

 slightly shorter than the rather unequal lower ones; the palet wanting. — 

 Swamps, X. J. and southward. Oct. 



4. A. per6nnans, Tuckerm. (Thix-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 floiver-bearing from or below the middle ; flowering glume awnless (rarely 

 short-awned), shorter than the unequal lower ones ; the palet minute or ob- 

 solete. — Damp shaded places. July, Aug. — Spikelets, etc., as in n. 5, into 

 which it seems to vary. 



5. A. seabra, Willd. (Hair-Grass.) (PI. 7, fig. 3.) Culms very slen- 

 der, erect (1-2° high) ; leaves short and narrow, the lower soon involute (the 

 upper 1-3' long, less than V wide) ; panicle very loose and divergent, pur- 

 plish, 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 hol- 

 lows of rocks, etc. — A variety (?) from about the White Mountains, etc. (var. 

 montana, T acker m.), has a more or less exserted awn. 



6. A. canina, L. (Brown Bext-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 pur- 

 plish, rarely pale or greenish (1 - 1^" long). — Meadows, sparingly naturalized 

 eastward. A mountain form with shorter and more spreading panicle (A. 

 Pickeringii & A. concinna, Tuckerm., A. canina, var. alpina, Oakes, &, Ed. 2, 

 and essentially A. rubra, L. ex WahL, and A. borealis, Hartm.) is indigenous 

 •n mountain-tops, Maine to N. Y. ; also an ampler form in the Alleghanies of 

 Penn. and southward (A. rupe'stris. Chapman, etc.). July -Aug. (Eu.) 



30. P O L Y P 6 G O N, Desf. Beard-Grass. (PI. 8.) 



Spikelets 1 -flowered, in a contracted, mostly spike-like panicle. Empty 

 glumes nearly equal, long-awned, much longer than the membranaceous 

 flowering one which is commonly short-awned below the apex. Stamens 3. 

 Grain free. (Name composed of ttoXv, much, and ircoycov, beard.) 



P. MoxsPELiExsis, Desf. Panicle interrupted ; lower glumes oblong, the 

 awn from a notch at the summit, the flowering one also awned ; root annual. 



— Isles of Shoals {Robbins), ballast heaps, and southward. (Nat. from Eu.) 



