Chase — Notes on Genera of Panicea. W. 107 



Inflorescence paniculate or of slender subsimple 

 racemes, these digitate. 

 Spikelets never silky-pubescent, nor ciliate- 

 margined, often scabrous or hispid. 

 Spikelets ovate, not having a callus-like 



Imse 2,7. Echinochloa. 



■ Spikelets lanceolate, with a long callus-like 

 base below the long-awned glumes. 



28. Chaetium. 

 Spikelets silky pubescent or with a conspic- 

 uously ciliate margin ; fruit subindurated. 

 Second glume and sterile lemma 2-lobed, a 

 slender awn from between the lobes; 

 fruit awnless; first glume remote; in- 

 florescence paniculate . . .29. Tricholaena. 

 Second glume and sterile lemma not lobed ; 

 fruit awned; first glume not remote; 

 inflorescence of digitately arranged, 

 subsimple racemes. 

 Sterile lemma and glumes papery, not at 

 all indurated; fruit stipitate. 



30. Coridochloa. 

 Sterile lemma subindurated similar to the 



fertile lemma 31. Alloteropsis. 



Spikelets subtended or surrounded by 1 to many bristles or 

 spines (sterile branchlets), these distinct or more or less 

 connate at base, forming a pseudo-involucre. 

 Spikelets deciduous, bristles persistent. 



Spikelet with lower floret as well as the upper perfect and 



with indurated lemma and palea 34. Dissochondrus. 



Spikelet with upper floret only perfect. 

 Sterile palea at maturity becoming cartilaginous and 

 winged, much exceeding the spikelet in width; 

 spikelets secund along the branches of a simple pan- 

 icle, each subtended by a single viscid bristle. 



35. Ixophorus. 

 Sterile palea not enlarged at maturity. 

 Second glume and sterile lemma very broad, many- 

 nerved, the glume saccate, auriculate, the lemma 

 lyre-shaped, indurated on the margins ; the spike- 

 let subtended by a single flexuous bristle . 32. Setariopsis. 

 Second glume and sterile lemma not many-nerved, 

 saccate, auriculate nor lyre-shaped; subtending 



bristles 1 to many 33. Chaetochloa. 



Bristles falling with the spikelets at maturity (in the culti- 

 vated Pennisetum americanum the globose grain falls 

 from the usually persistent spikelet, with or without the 

 lemma and palea attached). 



