280 MONOCOTYLEDENOUS. 



Genus XXXII ELYMUS. 



SpiJceJets 2, or more at each joint of the rachis, 3-9-flower- 

 ed. Glumes 2, nearly equal, sometimes ai^sent, lower palea 

 entire, with a short awn, upper one bitid. Scales ovr te, hairy. 



1 E ViRGiNicus. Stem erect, glabrous. Leaves scabrous, wifh scabrous 

 sheaths. Glumes 2, somewhat Jatera), terminating by an awn, the exterior 

 palea concave, awned, about the size of the interior. 



'21- June — Aug. I. ry soils. 2- 3 ft. 



2 E Sriatus. Sj^i^e erect; spikelets 2-flowered, awned, hispid, in pairs. 

 Glumes linear, awned. Qfem erect, striate. Leaves lanceolate, acuminate, 

 upper surface scabrous. Iiachis pubescent. 



% June. Shady woods. 8-12 in. 



3 E HysTRix. SpiJie erect ; spikelets expanding, 4-flowered, destitute of 

 glumes. Faleae dabrous. Leaves glaucous. 



% July. Mountains 2-3 feet. 



Genus XXXIII ROTTBOLLIA. 



Flowers i;i l-sidcd spikes. Glumes 1-2-flowered, the flow- 

 ers sterile and perfect. 



1 R DiMiDiATA. Stem creeping, branching, glabrous. Leaves glabrous, 

 sometimes opposite, perennial. Sp'^es terminal, flat. G/t^wes unequal, the 

 exterior shortest, Paleae lanceolate, the exterior longest. 

 % Through the summer. On the sea coast. 



GexNUs XXXIV SPARTINA. 



Flowers in one sided spikes, imbricate, in 2 rows. Glumes 

 2, unequal, keeled. Palem 2, unequal, without awns. 



1 S JuNCEA. Stem glabrous, columnar. Leaves linear, convolute when 

 old. S/?ea<As glabrous, ciliate at the throat. Spikes few, pedunculate ; exte- 

 rior glume small, the interior one long, keeled ; exterior palea shortest, the 

 interior compressed, as long as the glume. 



% Through the summer. Sea coast. 2-3 ft. 



2 S PoLYSTACHYA. Stem glabrous, columnar. Leaves broad, very long, 

 scabrous on the upper surface. Sheath longer than the joints, with the throat 

 hairy. Spihes numerous, 10-12 expanding, alternate. 



% September. On the sea coast. 3-10 ft. 



3 S Glabra. Stem glabrous, listular. Leaves long, glabrous, concave 

 Spikes erect, appressed 5-8. Glumes and pal ae ciliate on the keels, 



%. August — Sept. On the sea coast. 2-4 ft. 



SACHARlNEiE. 



Iiifiorescence spiked, or panicled. Glumes not keeled. 

 PalecB thin, membranaceous, without keels, the lower one com- 

 monly bearded. 



Genus XXXV. ANDROPOGON. 



Flowers polygamous, spiked. Spikelets in pairs, 1-2-flow- 

 ered, the lower ones sterile, or when but one it is perfect. 



