22 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



and staminate together in the same spike; glumes usually firmer than the 

 lemma and palea, sometimes awned, the lemma awnless. 



This small and unimportant tribe is known also as Nazieae. In Zoysia the 

 spikelets are single and have only 1 glume, this coriaceous, much firmer than 

 the lemma and palea, the palea sometimes obsolete. 



Key to the genera of Zoysieae 



Spikelets single; first glume wanting '. 94. Zoysia. 



Spikelets in clusters of 2 to 5; first glume present. 



Spikelets bearing hooked spines on the second glume, the group forming a little bur. 



93. Tragus. 

 Spikelets not bearing hooked spines, the second glume mostly cleft and awned. 



Groups of spikelets erect, the inflorescence not 1-sided 95. Hilaria. 



Groups of spikelets nodding along one side of the delicate axis 96. Aegopogon. 



TRIBE 7. CHLORIDEAE 



Spikelets 1- to several-flowered, in 2 rows on one side of a continuous 

 rachis, forming 1-sided spikes or spikelike racemes, these solitary, digitate, or 

 racemose along the main axis. 



A large and rather important tribe, confined mostly to warm regions. 

 The group is heterogeneous, the only common character of the genera (aside 

 from the characters that place them in Festucoideae) being the arrangement 

 of the spikelets in 1-sided spikes. Chloris and the allied genera form a coherent 

 group, in which the spikelet consists of 1 perfect floret and, above this, 1 or 

 more modified or rudimentary florets. Leptochloa, Eleusine, and their allies, 

 with several-flowered spikelets, are more nearly related to certain genera 

 of Festuceae. The spike is reduced to 2 or 3 spikelets or even to 1 spikelet and 

 is sometimes deciduous from the main axis (Cathestecum and Sect. Atheropogon 

 of Bouteloua). In Ctenium there are 2 sterile florets below the perfect one. 



Key to the genera of Chlorideae 



Plants monoecious or dioecious. Low stoloniferous perennial 115. Buchloe. 



Plants with perfect flowers. 



la. Spikelets with more than 1 perfect floret. 

 Inflorescence a few-flowered head or capitate panicle hidden among the sharp-pointed 



leaves. Low spreading annual 114. Munroa. 



Inflorescence exserted. 



Spikes solitary, the spikelets distant, appressed, several-flowered.... 99. Tripogon. 

 Spikes more than 1 (sometimes 1 in depauperate Eleusine). 

 Spikes numerous, slender, racemose on an elongate axis. 



Rachilla and callus of floret glabrous or nearly so; glumes acute, less than 5 mm. 



long 97. Leptochloa. 



Rachilla and callus of floret strongly pilose; glumes long-acuminate, about 1 cm. 



long 98. Trichoneura. 



Spikes few, digitate or nearly so. 



Rachis of spike extending beyond the spikelets 101. Dactyloctenium. 



Rachis not prolonged 100. Eleusine. 



lb. Spikelets with only 1 perfect floret, often with additional imperfect florets above or 

 below. 

 2a. Spikelets without additional modified florets, the rachilla sometimes prolonged. 

 Rachilla articulate below the glumes, the spikelets falling entire. 



Glumes unequal, narrow 107. Spartina. 



Glumes equal, broad, boat-shaped 106. Beckmannia. 



Rachilla articulate above the glumes. 



Spike solitary, slender, arcuate 102. Microchloa. 



Spikes 2 to many. 



Spikes digitate; rachilla prolonged 103. Cynodon. 



Spikes racemose along the main axis; rachilla not prolonged. 



Spikes slender, divaricate, the main axis elongating and becoming loosely 



spiral in fruit 105. Schedonnardus. 



Spikes short and rather stout, appressed, the axis unchanged in fruit. 



104. Willkommia. 



