648 GRAMINE&. (GRASS FAMILY.) 



2. A. exarata, Trin. Culms erect, 1-2 high; leaves mostly erect; 

 panicle narrow, crowded, greenish, the rays mostly flower-bearing to the base ; 

 spikelets 1^-2" long; glumes nearly equal, acute, the flowering ones shorter, 

 sometimes awued above the middle. Wise. (Vasey) to Sask., and far 

 westward. 



2. TRICH6DIUM. Palet abortive, minute, or none. 



3. A. elata, Triu. Culms Jinn or stout (2 -3 high); leaves flat (1-2" 

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

 of the spreading panide above the middle (1|" long) ; flowering glume awnless, 

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

 Swamps, N. J. and southward. Oct. 



4. A. perennans, 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 aimless (rarely 

 short-awued), 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. SCabra, 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 1" wide) ; panicle very loose and divergent, pur- 

 plish, the long capillary brandies 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 ; those are whorled, 

 rough with very minute bristles (under a lens), as also the keel of the glumes. 

 Spikelets \" long. A dwarf mountain form occurs, growing in tufts in hol- 

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

 montaua, Tuckerm.), has a more or less exserted awn. 



6. A. canina, 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 

 exsertiy awned on the back at or below the middle; spikelets brownish or pur- 

 plish, rarely pale or greenish ( 1 - l\" 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 

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

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



30. POLYPOGON, 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 membrauaceous 

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

 Grain free. ( Name composed of iroKv, much, and troiydiv, beard.) 



P. MONSPELIENSIS, 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 Ku.) 



