PANlCEifi 45 



CHAPTER VI 



Series I. — Panicacece. 



TRIBE I— PANICKY. 



This is a fairly large and important tribe flourishing mostly in 

 the warm regions and the tropics. It is very well represented in 

 South India and fifteen genera are met with. 



The inflorescence varies very much within this tribe and 

 consists of spikes, racemes and panicles. The spikelets are usually 

 four-glumed and contain one terminal perfect flower and a stami- 

 nate or neutral flower below. But in the genus Isachne both the 

 flowers are perfect. In some grasses the spikelets contain only 

 staminate'or pistillate flowers. In Coix and Polytoca the plant 

 bears both male and female spikelets in the same inflorescence, 

 but in Zea on the same plant they occur as distinct inflorescences. 

 The littoral grass Spinifex is dioecious. 



The first glume of the spikelet is the smallest. In Panicum it is 

 nearly two-thirds or less than the third glume. It is very small in 

 Digitaria and entirely suppressed in Paspalum. In Eriochloa it is 

 reduced to a minute ridge lying just close to the swollen ring-like 

 joint of the rachilla. The second and the third glumes are more 

 or less equal and similar in texture. The fourth glume becomes 

 firm and rigid along with its palea and usually encloses the 

 grain. 



The pedicel is jointed in some genera and in others it is conti- 

 nuous with the spikelet and not jointed. When mature the 

 spikelets fall away either by themselves, singly with their pedicels 

 or in groups with portions of rachis, according to the position of 

 the joint. Bristles (branchlets) are often found on the pedicels. 

 In Setaria a few are borne by the pedicels. The bristles form a 

 regular involucre at the base of a group of spikelets in Pennisetum, 

 and in Cenchrus these become united at the base into a mass 

 forming a kind of burr around the spikelets. 



KEY TO THE GENERA. 



A. Spikelets articulate on their pedicels. 



B. Spikelets without involucels. 



C. Spikelets dorsally flattened, awnless. 



Inflorescence racemed ; glumes 

 three ; nerves of second glume 

 five or less, side nerves curved ... I. Paspalum. 



Inflorescence digitate ; glumes 

 three with a minute glume ; 

 nerves of second glume five to 

 seven, straight and prominent • ■• 2. Digitaria. 



