314 



paniculate, consisting of Bpikelets composed of two to many 2-ranked 

 imbricated bracts (glumes), the two lowesi normally empty, one or 



both of those sometimes wanting or very much reduced. One or more 

 of the upper glumes excepi sometimes the terminal ones contains in the 

 axil a Sower which is usually Inclosed by the brad like palea. Flowers 

 perfect or staminate, sometimes dioecious or monoecious, subtended by I 

 to 3 minute hyaline scales (lodicules). Stamens 1 to 6, usually 3 ; anthers 

 2-celled, versatile. Ovary L-celled, L-ovuled; styles 1 to .'!, commonly 2; 

 stigmas hairy or plumose. Fruit a seed-like grain (caryopsis). 



Genera aboul 335; species about 3,500, widely distributed in all parts 

 of the world, the greater number of species being found in the Tropics 

 hut the greater number of individuals being found in temperate regions. 



KEY 'I'D THE TRIBES AND GENERA. 



I. Spikelets one, rarely two-flowered, lower flower when present 

 Imperfect, falling from the pedicel entire or with certain joints 

 of the rhaehis at maturity. Rhachilla not produced beyond 

 the flowers. 



2. Spikelets cylindrical or somewhat dorsally compressed ; 

 empty glumes manifest ; hilum punctiform. 



:;. Flowering glumes and palea hyaline, much more 

 delicate in structure than the thick- membranous 

 to cartilaginous empty glumes. 



4. Spikelets unisexual on separate inflores- 

 cences or on different parts of the same 



inflorescence 1. Mavok.k 



4. Spikelets in pairs, one sessile, one pedicel- 

 late in the same Inflorescence, the former 

 perfect, tin 1 latter staminate or empty, 



rarely perfect II. AHDROPOGONE/B 



3. Flowering glumes, at least ol the perfect flo'W i r. 

 similar in texture to the empty glumes or fre- 

 quently thicker, never hyaline and thin. 

 i. Flowering glume and palea membranous. 



5. Inflorescence spicate ; spikelets fall- 

 ing singly or in groups, the first 

 glume usually larger than tin- rest III. ZOI8IE.fi 

 5. Inflorescence paniculate ; spikelets de- 

 ciduous singly from the ultimate 

 branchlcts of the inflorescence, the 

 first glume usually smaller or nar- 

 rower than the rest I V. Tkistkc.ink.k 



4. Flowering glume and palea cfaartaceous, car- 

 tilaginous, or coriaceous, very different 

 in color and appearance from the empty 



glumes V. I'.wi. r.i: 



2. Spikelets much compressed laterally ; empty glumes none 



or rudimentary ; hilum linear . VI. Ouyzk.k 



I. Spikelets one to many (lowered, the empty glumes persistent, 

 the rachilla generally articulated above the empty glumes 

 and produced beyond the upper glume, the upper glumes fre- 

 quently empty. 



2. Stems herbaceous : leaf-blades sessile, not articulated with 

 the sheath. 



:!. Spikelets pedicellate in panicles, spike-like panicles 

 or racemes. 



1. Spikelets one-flowered. 



fi. Empty glumes four ; palea one- 

 nerved VII. 1'n \i.\uiDi:.i: 



5. Empty glumes two; palea two-nerved.. VIII. AOROSTIDBfi 



