20 BULLETIN 772, U. S. DEPARTMENT OF AGRICULTURE. 



Key to the genera of Paniceae* Continued. 



12a. Spikelets in slender racemes more or less digitate at the 



summit of the culms 110. SYNTHEBISMA. 



12b. Spikelets in panicles 13 



13a. Fruiting lemma boat shaped; panicles narrow. 



108. ANTHAENANTIA. 



13b. Fruiting lemmas convex; panicles diffuse 111. LEPTOLOMA. 



lOb. Fruit chartaceous-indurate, rigid 14 



14a. Spikelets placed with the back of the fruit turned away from 



the rachis of the racemes, usually single (not in pairs) 15 



15a. First glume and the rachilla joint forming a swollen ring- 

 like callus below the spikelet 113. ERIOCHLOA. 



15b. First glume present or wanting, not forming a ringlike 



callus below the spikelet 16 



16a. First glume present ; racemes racemose along the main 



axis , 114. BRACHIARIA. 



16b. First glume wanting ; racemes digitate or subdigitate. 



115. AXONOPUS. 

 14b. Spikelets placed with the back of the fruit turned toward the 



rachis of the spikelike racemes, or pedicellate in panicles 17 



17a. Fruit long-acuminate; both glumes wanting- 116. REIMAROCHLOA. 



17b. Fruit not long-acuminate, at least one glume present 18 



ISa. First glume typically wanting; spikelets plano-convex, 



subsessile in spikelike racemes 117. PASPALUM. 



ISb. First glume present ; spikelets usually in panicles 19 



19a. Second glume inflated-saccate, this and the sterile 

 lemma much exceeding the stipitate fruit. 



120. SACCIOLEPIS. 



19b. Second glume not inflated-saccate 20 



20a. Culms woody and bamboolike; fruit with a 



tuft of down at the apex 119. LASIACIS. 



20b. Culms herbaceous ; no tuft of down at the apex 



of the fruit 118. PANICUM. 



TRIBE 13, ANDROPOGONEAE. 



Spikelets in pairs along a rachis, the usual arrangement being 

 one of the pair sessile and fertile, the other pedicellate and staminate 

 or neuter, or rarely wanting, only the pedicel present ; fertile spike- 

 let consisting of one perfect terminal floret and, below this, a stami- 

 nate or neuter floret, the lemmas thin or hyaline, and two awnless 

 glumes, one or usually both firm or indurate. 



A large tribe, confined mostly to warm regions. The rachis is 

 usually jointed, disarticulating at maturity, with the spikelets at- 

 tached. In a few genera it is thickened. Sometimes the racemes are 

 shortened to 1 or 2 joints and borne on branches, the whole forming a 

 panicle (as in Holcus and Sorghastrum) instead of a series of 

 racemes. In a few genera the spikelets of the pair are alike. In 

 Traclwpogon the fertile spikelet is pedicellate and the sterile one 

 nearly sessile. 



