GENERA OF GRASSES OF THE UNITED STATES. 17 
Key to the genera of Chlorideae—Continued. 
7a. Spikelets without additional modified florets, the rachilla sometimes 
OPO MSG, See Eh seas ak as ae ee i pa ads Beye Dp yall ag Da 8 
8a. Rachilla articulate below the glumes, the spikelets falling entire_ 9 
Sa GlamMes anequal, Marrow 222 5s Bee ee ee 90. SPARTINA. 
9b. Glumes equal, broad and boat shaped__________ 89. BECKMANNIA. 
8b. Rachilla articulate above the glumes_______________-__________ 10 
10a. Spikes digitate; rachilla prolonged________________ 86. CAPRIOLA. 
10b. Spikes racemose along the main axis; rachilla not prolonged_ 11 
lla. Spikes slender, divaricate, the main axis elongating and 
becoming loosely spiral in fruit_______ 88. SCHEDONNARDUS. 
11b. Spikes short and-_rather stout, appressed, the axis un- 
Ch EW AVSXEVO Wan Uae oh YUH REMMI ae 87. WILLKOMMIA. 
7b. Spikelets with 1 or more modified florets above the perfect one______ 12 
12a. Spikelets with 2 sterile florets below the perfect one; second 
glume bearing a squarrose spine on the back; spike single, 
TREY CATON G65 0 [ea Na aaa CEI ca sh I aR 91. CAMPULOSUS. 
12b. Spikelets with no sterile florets below the perfect one; second 
glume without a squarrose spine; spikes usually several______ 13 
Ae SPIKES TO1SiLALe! OF MEA TI V7, SO meee eee ee ae Se in 14 
14a. Fertile lemma 1-awned or awnless_____________ 93. CHLORIS. 
14b. Fertile lemma 3-awned____________________ 94. TRICHLORIS. 
18b. Spikes racemose along the main axis______________________ 15) 
15a. Spikelets distant, appressed; spikes slender, elongate. 
92. GYMNOPOGON. 
15b. Spikelets contiguous or crowded, not appressed; spikes 
usually Shon and) rauheres tO Ube. sun ecm AR aaa 16 
16a. Spikelets 3 in each spike, the 2 lateral staminate or 
rudimentary ; spikes falling entire___ 96. CATHESTECUM. 
16b. Spikelets 2 to many (rarely 1) in each spike, all 
alike ; spikes usually persistent, the florets falling. 
95. BouUTELOUA. 
TRIBE 8, PHALARIDEAE. 
Spikelets with one perfect terminal floret and, below this, a pair of 
staminate or neuter florets. 
A small tribe of about six genera, only three of which are found 
in the United States. In Phalaris the lateral florets are reduced to 
minute scalelike lemmas closely appressed to the edges of the fertile 
floret. In Torresia the lateral florets are staminate and as large as 
the fertile floret. 
Key to the genera of Phalarideae. 
la. Lateral florets staminate; spikelets brown and shining. ____ 99. ToRRESIA. 
1b. Lateral florets neuter; spikelets green or yellowish______-_--»-_--_ 2 
2a. Lateral florets reduced to small awnless scalelike lemmas; spike- 
lets much compressed laterally______________.______ 101. PHALARIS. 
2b. Lateral florets consisting of awned hairy sterile lemmas exceed- 
ing the fertile floret ; spikelet terete___.______ 100. ANTHOXANTHUM. 
97769°—19—Bull. 772-2 
