Hitchcock — 7Vic Grasses of Hawaii 109 



Spikelets with only i perfect floret, often with additional imperfect florets above. 



Rachilla prolonged but with no imperfect florets 26. Capriola (p. 161 ) 



Rachilla bearing i or more modified florets above the perfect one. 



Spikes digitate or nearly so 27. Chloris (p. 163) 



Spikes racemose along the main axis 28. Boutelgua (p. 165) 



PHALARIDEAE. 



Glumes much shorter than the spikelet 29. ]\IicrolaEna (p. 167) 



Glumes not shorter than the spikelet. 



Lateral florets consisting of awned hairy sterile lemmas exceeding the fertile floret; spikelet 



terete 30. Anthoxanthum (p. 167) 



Lateral florets reduced to small awnless ■ scalelike lemmas ; spikelets much compressed 

 laterally 31. Phalaris (p. 169) 



PANICEAE. 



Spikelets sunken in the cavities of the flattened cork)- rachis 34. StenoTaphrum (p. 177) 



Spikelets not sunken in the rachis. 



Spikelets subtended or surrounded by i to many distinct or more or less connate bristles, 

 forming an involucre. 

 Bristles united into a burlike involucre, the bur falling entire.. ..44. Cenchrus (p. 209) 

 Bristles not united, persistent, the spikelets deciduous. 



Lower floret sterile 42. Chaetochloa (p. 205) 



Lower floret fertile -—43. Dissochondrus (p. 209) 



Spikelets not subtended by bristles. 



Glumes or sterile lemma awned (awn short and concealed in the silky hairs of the 

 spikelet in Tricholaena, awn reduced to a point in Bchinochloa colonum). 



Liflorescence paniculate; spikelets silky 41. Tricholaena (p. 204) 



Liflorescence of unilateral simple or somewhat compound racemes along a common 

 axis; spikelets smooth or hispid, not silky. 

 Blades lanceolate, broad and thin ; glumes 2-lobed, awned from between the 



lobes 39. Oplismenus (p. 201 ) 



Blades long and narrow : glumes awned from the tip 



-..40. ECHINOCHLOA (p. 202) 



Glumes and sterile lemma awnless. 



Fruit cartilaginous-indurate, flexible, usually dark colored, the lemma with more or 

 less prominent white hyaline margins, these not inrolled. 



Spikelets covered with long silky hairs, arranged in racemes, these panicled 



.32. Valota (p. 170) 



Spikelets glabrous or variously pubescent, but not long-silky, arranged in 



slender racemes, more or less digitate at the summit of the culms 



33. SynthErisma (p. 170) 



Fruit chartaceous-indurate, rigid. 



Fertile florets 2 in each spikelet 38. Isachne (p. 201) 



Fertile floret i in each spikelet. 



First glume typically wanting (sometimes found in P. distich iiiii) ; spikelets 



plano-convex, subsessile in spikelike racemes 



35. Paspalum (p. 177) 



First glume present ; spikelets usually in panicles. 



Second glume inflated-saccate, this and the sterile lemma much exceed- 

 ing the stipitate fruit 37. SacciolEpis (p. 199) 



Second glume not inflated-saccate 36. Panicum (p. 181) 



ANDROPOGONEAE. 



Spikelets all perfect; inflorescence of 2 straight digitate racemes 45. IschaEmum (p. 213) 



Spikelets not all perfect, the sessile perfect, the pediceled staminate or rudimentary. 



Fertile spikelet with a hairy-pointed callus, formed of the attached supporting rachis joint 

 or pedicel. 



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