30 FLOBA OF PHILADELPHIA. 



Spikelets with the upper scales flower-bearing, or narrow and abor- 

 tive. 

 Stigmas placed at or near the apex of the ovary. 



Scales more or less strongly compressed and keeled. 

 Empty basal scales 3-6; spikelets flat, 2-edged. 



55. Uniola. 

 Empty basal scales 2; spikelets flattened. 



Panicle contracted ; spikelets dioecious. 



56. DUtichlis. 

 Panicle open ; spikelets perfect. 



Flowering scales herbaceous, awn-pointed; 

 spikelets collected into one-sided clusters. 



57. Dactylis. 

 Flowering scales scarious-margined; rachis 



glabrous or with webby hairs. 

 .58. Poa. 

 Scales rounded on the back, at least below. 



Obtuse or siibacute and scarious at the apex, usually 

 toothed. 

 Plainly 5-7-nerved; styles present. 



59. Panicularia. 

 Obscurely 5-nerved; no style. 



60. Puccinellia. 

 Acute, pointed or awned at the apex. 



61. Festuca. 

 Stigmas plainly arising below the apex of the ovary; scales 



mostly awned. 62. Bromus, 



Tribe X. HOEDBAE. 



Spikelets solitary at the notches of the rachis. 



Flowering scales with their backs turned to the rachis. 



63. Lolium. 

 Flo^^'ering scales with their sides turned to the rachis. 



64. Agropyron. 

 Spikelets 2-6 at each joint of the rachis; scales mostly long-awned. 



Spikelets 1-flowered or with the rudiment of a second flower. 



65. Hordeum. 

 Spikelets 2-many-flowered. 



Empty scales a little smaller than the flowering ones. 



66. Flymus. 

 Empty scales very small or none. 67. Hystrix. 



Tribe XL BAMBUSEAE. 



Tall canes with large, flat spikelets in panicles or racemes. 



68. Arundinaria. 



1. TEIPSACUM L. 



1. Tripsacum DACTYLOiDES L. Gama-grass, Sesame-gniss. M. p. 67. Moist 

 soil. Summer. 

 P/H'/odeZp/iia— Bartram's Garden (B. Sm.). DetoR-are— Painter 's Ar- 

 boretum (Fu.). Chester — (P.). Lancaster — Islands, York Furnace ((Jr.) 

 (Le.), Fites Eddy (St.). 5ec^s— Near Eeading (P.). 



Cape Ifai/— Cape May, I. Burk (He.). Atlantic— IS! ear Egg Harbor 

 (C). Monmouth — Monmouth Beach Center (C). 

 Neiv Castle — Above AUapokas. 



