452 GRAMINACE^E. 



H.jubatum Linn. : lateral flowers abortive, neutral ; bristles of the glume 

 and lower palea 6 times as long as the flowers. 



Marshes. Subarct. Amer. to Mass. W. to the Platte River. June. (g). 

 Culm 2 feet high, simple, smooth, slender. Leaves rather short, rough on the 

 margin. Spike 2 3 inches long. Wild Barley. Squirrel-tail Grass. 



XI. RoTTBffiLLE-as. Spikekts I- or 2- rarely 3-flowered, seated in 

 an excavation of the rachis, either solitary or in pairs, with one pedicel- 

 late and often blighted. One flower of each %-flowered spikelet imper- 

 fect. Glumes 1 2, sometimes wanting, ?nostly coriaceous. Palecc 

 membranaceous, rarely awned. 



54. TRIPSACUM. Linn. Sesame Grass. 



(From the Greek rpt/?w, to grind ; but the application is obscure.) 

 Monoecious. STERILE SPIKELETS in pairs on each joint of the 

 rachis, and longer than the joint, collateral, 2-flowered. Flow- 

 ers each with 2 palaee. FERTILE SPIKELETS solitary, as long 

 as the joint, 2-flowered. Flowers with 2 paleae ; the outer or 

 lower flower neutral, the inner or upper one fertile. Spikes 

 solitary, or digitate in twos or threes. 



T. dadyloides Linn. : spikes 2 3, aggregated or digitate, sometimes sol- 

 itary ; sterile flowers above, fertile at the base. 



Meadows. N. Y. to Car. W. to Miss, and Ark. July, Aug. %.Culm 

 erect or oblique, 4 6 feet high, somewhat compressed. Leaves large, often 3 

 feet long, linear-lanceolate, smooth beneath, rough above. Spikes usually 2 3, 

 rachis articulated. T. mcmostachyon Willd. is a mere variety with a single 

 spike. The value of this grass for fodder, seems to have been greatly overrated. 



Sesame-grass. Gama-grass. 



XII. ANDROPOGONEJE. Spikelets S-flowered ; the lower flower al- 

 ways imperfect, on a bearded pedicel. Palea mostly hyaline. 



55. ANDROPOGON. Linn. Beard Grass. 



(From the Greek avep, a man, and Truy wv, a beard ; in allusion to the hairy 

 flowers.) 



Lower flower staminate or neutral, the glumes and paleae 

 often very minute or wanting. Upper flower perfect. Glumes 

 awnless. Palese 2, shorter than the glumes ; lower one mostly 

 awned. Flowers in panicles or spikes. 



* Flowers in panicles. 



1. A. nutans Linn. : panicle terminal, oblong, branched, at length nod- 

 ding ; lower flower a mere pedicel, without valves ; outer glume of the per- 

 fect flower covered with brownish hairs ; awn contorted. A. avenaceum 

 Mich. 



Sandy sterile fields. Throughout the U. S. Aug. Oct. 1\.. Culm 3 6 

 feet high, simple, terete. Leaves a foot or more long, glaucous. Panicle loose, at 

 first erect, at length nodding. Nodding Beard-grass. Indian-grass. 



