50 



GRAMINEiE. 



2. A. capiilaris Host. Fixe Hair-grass. Resembling A. caryo- 

 phyllea but the panicle much more open; spikelets less numerous and 

 not tufted, only 1 line long; pedicels longer and sometimes glabrous; 

 bractlet of the lower flower awnless, of the upper awned; awns 

 hygroscopic. 



Naturalized from southern Europe: Tocaloma, 1893, Miehener and 

 Bioletti; Humboldt Co., Davy and probably occurring elsewhere but 

 perhaps confused with the preceding. May. 



18. DESCHAMPSIA Beam. 

 Panicle mostly open (rarely contracted), branches slender. Spike- 

 lets small, 2-flowered ; flowers both perfect, somewhat distant, lower 

 sub-sessile, upper pedicellate; rachilla jointed, hairy, prolonged beyond 

 the insertion of the upper flower-enclosing bractlet as a hairy bristle 

 which is sometimes terminated by an empty bractlet. Bracts equal- 

 ing or exceeding the uppermost flower-enclosing bractlet, thin mem- 

 branaceous, 1 to 3-nerved, keeled, acute; margins and apex thinly sca- 

 rious. Bractlet membranaceous or nearly hyaline, 2-toothed or cleft, 

 or truncate and denticulate, with a fine dorsal awn below the middle; 

 palea narrow, prominently 2-nerved, often 2-toothed. Stamens 3. 

 (Dr. Desehamps, a French physician and naturalist of St. Omer. natu- 

 ralist to the La Perouse relief expedition. Grasses with the shining 

 spikelets of Trisetum and Aira, usually smaller than in the former, 

 larger than in the latter with which genus they were formerly united; 

 stems usually stouter than in Aira.) 



Stems stout, from a tufted rootstock; bracts barely equaling, and mostly 

 shorter than the whole spikelet: the lower 1-nerved; panicle contracted, 

 erect or somewhat drooping, dense and somewhat spikelike; branches 

 short, stoutish; awn stout, straight 1. D. holciformis. 



Stems slender, weak; bracts exceeding the uppermost bractlet. 

 Perennial. 



Panicle-branches several at a node, very unequal in length, mostly 

 appressed, bearing many spikelets; spikelets \y 2 to 2 lines long; bractlet 

 obscurely nerved or nerveless; achene grooved. . . 2. D.elongata. 

 Panicle racemose, 1 to 2 in. long; branches appressed, with few spikelets. 



Diminutive plant, 3 to 4 in. high 2. D. elongata 



var. tenuis. 



Annual; panicle-branches mostly in 3's below, in pairs or solitary above, 

 distant, mostly spreading and bearing few (about 5) spikelets at the ends; 

 spikelets 2% to \% lines long; bractlet 5-nerved. . . . 3. D. calycina. 



1. D. holciformis Presl. California Hair-grass. Perennial: 

 rootstock forming large, dense tufts; stems 2 to 5 ft. high, stout, aris- 

 ing from a dense tuft of involute leaves; ligule 1 to 2 lines long; pani- 

 cle contracted, dense, erect or somewhat drooping, 6 to 10 in. long; 

 branches many at a node, sub-erect, the longest lj to 2£ in. long, 

 branched and spikelet-bearing almost to the base; spikelets 2h to 3 

 lines long, short-pediceled, usually purplish-tinted below, yellowish 

 to brown above; tracts barely equaling, and mostly shorter than the 

 whole spikelet, acute; bractlet membranaceous, silky-hairy at base, 

 rather regularly 4-toothed; awn stout, about 1£ lines long, inserted 

 near the base of the bractlet, usually shortly exserted; anthers 1 line 

 long, purplish. — (Aira holciformis Steud.) 



