351 



(2!)) PANICUM Linn. 



Spikelots in spikes, racemes, or panicles, 1 to 2-fiowereil. First empty 

 glume usually smaller than the second and the latter as large as and 

 similar to the third which often encloses a staminate flower. Flowei-ing 

 glume and palea indurated, awnless or very short awned. 



Species about 350 in tlie tropical and temperate regions of the world; 30 in tlie 

 Philippines. 



1. Spikelets terete or dorsaUy compressed. 



2. Branchlets of the panicle not produced beyond the ter- 

 minal spikelets into awn-like bristles. 

 3. Spikelets 1 to 2-.seriate, close-set on the under- 

 side of the flat rhachis of a simple spike, the 

 spikes alternally arranged in a simple raceme. 

 (S Paspaloide.^.) 



4. Spikes shorter than the internodes (1) P. flavklum 



4. Spikes exceeding the internodes. 



5. Tip of spikes excurrent beyond the 

 upper spikelets, setiform ; second 

 glume one half as long as the 



flowering glume (2) P. pmictatum 



5. Tip of spikes not produced ; second 

 glume nearly as long as the flower- 

 ing glume (3) P. paspaloides 



3. Spikelets 3-4-seriate, crowded on the under sur- 

 face of a simple or branched spike, ovoid, the 

 empty glumes usually muricate and the second 

 and third cuspidate or rigidly awned. {% Echi- 



NOCHLOA.) 



4. Awn of the third glume very short or 

 almost wanting. 



5. A coarse erect grass (5) P. crus-ijaUi muticuin 



5. A slender low grass, the culms usually 



prostrate, at least below (4) P. voloiuon 



4. Awn of the third glume elongated, mostly 

 many times longer than the spikelet. 

 5. Erect ; panicles purplish ; spikelets 2 



to 3 mm. long (5) P. crus-i/alU 



5. Prostrate, aquatic ; panicles green ; 



spikelets 4 to 5 mm. long (6) P. stnijiiiiiuin 



3. Spikelets irregularly 1-2-seriate on slender or 

 spiciform branches of a simple raceme, solitary 

 or geminate, distant or crowded, not confined 

 to one .side of the rhachis. (§ Brachiaria.) 



4. Spikelets silky-villous (9) P. viUosuvi ' 



4. Spikelets glabrous. 



.5. First glume a.s long as the spikelet.... ( 7 ) P. ambii/uum 

 5. First glume two thirds as long as the 

 spikelet or less. 

 6. Spikelets 1.5 to 3 mm. long. 



7. Spikes about 2 cm. long ; 



spikelets 1..5 mm. long.. (8) P. prostratum 

 7. Spikes 3 to 4 cm. long ; 



spikelets 3 mm. long.... (10) P. rcmotum 

 6. Spikelets 4 mm. long ; tips of 

 the empty glumes thickened 



keeled-apiculate (11) P. crassiapiculatum 



3. Spikelets small, crowded in spiciform or narrow 

 cylindrical panicles (except P. auritum), the 

 flowering glume slightly indurated, narrow, 

 usually much shorter than the third glume. 

 (§ Hymenachne.) 



