316 



1. Spikelets heterogamous or rarely honiofeamous, the joints 

 of the axis of the raceme (false spike) appressed or 

 grown to the pedicels of the primary spikelets, forming 

 a hollow or excavation for the reception of the secondary 

 spikelets ; fertile glumes always awnless. 



2. Spikelets 2-nate ; first empty glume flat (12) RotthocUm 



2. Spikelets 2-nate; first empty glume globose (13) Manisiiris 



2. Spikelets solitary; first empty glume convex (14) OiiliiiirKs 



1. Spikelets heterogamous, the sessile hermaphrodite, rarely 

 pistillate, the pedicellate staminate, empty or wanting, 

 very rarely all hermaphrodite or all pedicellate : joints 

 of the racemes not strongly thickened, nor with excava- 

 tions for the reception of the spikelets. 

 2. Sessile spikelets 2-flowered. 



3. Racemes reduced to the terminal joint with 

 three spikelets, and enclosed by a sheath- 

 ing leaf or bract (17) Aplitda 



3. Racemes with many joints. 



4. Spikes rarely solitary ; spikelets 2- 



flowered, awned (\^) Ischacmum 



4. Spikes solitary ; spikelets l-flowered, 



the first glume pectinate (\(\) Ercniochloa 



2. Sessile spikelets l-flowered. 



3. A false whorl of four or more staminate or 

 empty spikelets at the base of each raceme ; 

 racemes usually subtended by a sheathing 



leaf (20) Thcmcda 



?>. No distinct whorl of staminate or empty 

 spikelets at the base of the racemes, or 

 where an imperfect one occurs, the ra- 

 cemes in pairs, subtended by a leaf-sheath. 

 4. Fertile glume awned from the back 



or base ; leaves cordate at the base.. (18) Arthraxon 

 4. Fertile glumes awned from the apex 

 or from a more or less deep cleft, 

 or awnless ; leaves not cordate at 

 the base (19) Andropof/nn 



Trihc in. ZOISIE^. 



1. Spike slender; spikelets narrow; first and second glumes 



awned (21) Perot ifi 



1. Spike rigid; spikelets appressed to the rhachis, not awned.. (22) Zaisid 



Trihc l\'. TRISTEGINEiE. 



1. Flowering glumes of the hermaphrodite flowers awned; 

 awns usually geniculate and twisted below ; slender 

 grasses (23) AnouUiirlla 



1. Flowering glumes awnless; spikelets minute; very coarse 



grasses (24) ThysanoUicna 



Tiilu' V. PANICE^. 



1. Spllfelets all perfect. 



2. Spikelets without any special covering or involucre 

 consisting of spines or bristles. 



3. Empty glumes two ; perfect flower one in 

 each spikelet. 



4. Lower empty glume witli a lliicketied 



ring-like callus (27» Kriiuhhxt 



4. bower empty glume without a ring- 

 like and thickened callus ; spikelets 

 In one-sided racemes or spikes. 

 .'). Spikelets ovate or orbicular, 



obtuse, rarely acute (2.5) Paspniiiin 



ft. Spikelets lanceolate, acute or 



acuminate (20) Dii/iliiria 



