315 



4. Spikelets two to many flowered. 



5. Flowering glumes usually shorter 

 than the empty ones, usually with 

 a bent awn on the baclt, rarely 



awned from the apex IX. Avene^ 



5. Flowering glumes generally longer 

 than the empty ones, unawned, or 

 with a straight awn from the apex.. XI. Festuce^e 

 ?>. Spikelets in two rows. 



4. Spikelets crowded on one side of the con- 

 tinuous rhachis, forming one-sided spikes 



• or racemes X. CHLORiDE.qi: 



4. Spikelets in two oppobite rows of the often 

 articulate rhachis, forming equilateral 



spikes XII. H0RDE.q5 



2. Stems woody ; leaf-blade with a petiole-like base which is 



articulated with the sheath XIII. Bambuse.^ 



Tribe I. MAYDEiE. 



1. Staminate spikes numerous in terminal panicles ; pistillate 

 spikes in the axils of the leaves subtended by large 

 membranous bracts at the base. 



2. Pistillate spikes of each leaf-axil free, articulated.... (1) EuihUicna 

 2. Pistillate spikes of each leaf-axil grown together 

 into a continuous, compound, and much thickened 



axis (2) Zea 



1. Staminate spikes solitary at the ends of the branchlets ; 

 pistillate below, one to two, each of them reduced to a 

 single splkelet entirely inclosed by the ovoid or spher- 

 ical, ivory-like sheath of the subtending bract (4) Coix 



1. Staminate and pistillate spikelets in the same spike, 



the lowest glume of the pistillate spikelets indurated... (3) Chionachne 



Tiilie I L. ANDROPOGONE^. 



1. Spikelets hombgamous, hermaphrodite ; joints of the rha- 

 chis not much thickened nor excavated for the reception 

 of the spikelet. 



2. Axis of the racemes continuous. 



3. Spikelets solitary, disposed in several slender 



unilateral racemes (^) Dimcria 



3. Spikelets in pairs, rarely in threes, upon 

 each joint of the rhachis, paniculate. 

 4. Racemes in a narrow, usually spike- 

 like panicle; spikelets awnless (G) Imjiprata 



4. Racemes in a board panicle ; spike- 

 lets usually awned (7) Miscanlhus 



2. Axis of the racemes articulate. 



3. Racemes solitary, terminal. 



4. Spikelets in pairs at each joint of 



the rhachis (11) Poi/oiiathcrum 



4. Spikelets in threes at each joint of 



the rhachis (10) Polijtrias 



3. Racemes two to many, digitate or approxi- 

 mate on a shortened main axis. 



4. Spikelets one, rarely two-flowered ; 

 when two flowered the first empty 

 glume with a median longitudinal 



furrow (9) PoUiiiin 



4. Spikelets two-flowered, the first empty 



glume without a longitudinal furrow.. (1.5) Urharmum 

 3. Racemes in a much-branched panicle upon 

 an elongated main axis, the lateral racemes 

 sessile (S) Haci-harnm 



