CHAPTER XVII 

 Tribe V. PANICEiE 



Spikelets with 1 terminal perfect floret and astaminate 

 or neutral floret below; fertile lemma firmer than the 

 glumes, often chartaceous; spikelets jointed on the pedicel 

 below the glumes. This large and important tribe is, like 

 Andropogoneae, found mostly in the tropics and warm 

 regions, but is well represented throughout the United 

 States, especially in the southern portion. The first glume 

 is usually absent in the large genus Paspalum and in a 

 few other genera, and in Reimarochloa and in certain spe- 

 cies of Paspalum the second glume also is absent. In 

 Eriochloa the first glume is reduced to a minute ridge 

 about the swollen ring-like lower joint of the rachilla. In 

 Isachne the lower flower is perfect like the upper. In this 

 tribe the spikelets are usually unawned but the glumes 

 are awned in Echinochloa, Oplismenus and Chtetium, and 

 the lemma in Tricholsena. What appear in some genera to 

 be awns are bristle-like branchlets. In Chsetochloa there 

 are 1 or more of these below all or some of the spikelets, the 

 bristles remaining after the fall of the spikelets. In Penni- 

 setum there is an involucre of bristles (branchlets) sur- 

 rounding the base of a cluster of spikelets, the bristles 

 being deciduous with the cluster. In Cenchrus the bris- 

 tles are retrorsely barbed and fused into a mass, forming 

 a bur around the spikelets. An Australian genus, Spinifex, 

 is dioecious and Olyra is monoecious. The fruit of Pani- 

 cum and of several other genera is a seed-like body con- 

 (176) 



