134 Gramineae 



75A. Branchlets of the panicle, or at least some of them, ending in a bristle 71. Setaria 



75B. Branchlets not ending in a bristle. 



76A. Panicle cylindric, dense; fertile floret pedicelled, crustaceous; upper glume swollen at base 72. Sacciolepis 



76B. Panicle effuse; fertile floret sessile, coriaceous or nearly so; upper glume not swollen at base 73. Fanicum 



74B. Inflorescence digitate or racemose; spikelets sessile or very short-pedicelled, alternate in 2 rows on one side of a 

 winged or wingless rachis. 



77A. Lemma of the fertile floret with hyaline membranous margins; lower glume minute or wanting 74. Digitaria 



77B. Lemma of the fertile floret without hyaline margins. 

 78A. Lower glume wanting. 



79A. Spikelets without an annular appendage at base; convex side of the floret and the upper glume facing the 



rachis 75. Paspalum 



79B. Spikelets with an annular appendage at base; flat side of the floret and the lemma of sterile floret facing the 



rachis 76. Eriochloa 



78B. Lower glume present. 



80A. Glumes and (or) sterile lemma awned; floret smooth. 



81A. Leaf-blades lanceolate, membranous 77. Oplismenus 



81B. Leaf-blades linear, elongate 78. Echinochloa 



SOB. Glumes and florets awnless; floret usually rugose 79. Bmchiaria 



73B. Both florets bisexual; inflorescence a panicle; spikelets pedicellate 80. hachne 



70B. Spikelets all unisexual; rigid littoral grasses with rigid pungent leaves; pistillate inflorescence a spiny head with long radiat- 

 ing branchlets each bearing a single spikelet near the base; staminate inflorescence umbellate, with several spikelets on 



each branch 81. Spinifex 



68B. Lemma of the upper floret thinly membranous, often with a long, geniculate, twisted awn, simulating in texture the lemma of 

 the lower floret; glumes chartaceous or rather coriaceous; spikelets usually geminate. 

 82A. Spikelets bisexual, often paired with a staminate or neuter spikelet. 



83A. Spikelets solitary at each node; inflorescence of 1 to many digitate continuous racemes 82. Dimeria 



83B. Spikelets geminate; racemes often articulate. 



84A. Spikelets all alike, bisexual; rachis of racemes slender, the internodes sometimes slightly inflated above. 

 85A. Rachis of the racemes not articulate, persistent, the spikelets falling. 



86A. Lemma of the bisexual florets bifid; lower glume coriaceous, rounded on back; racemes pedunded. . . 83. Eccoilopus 

 86B. Lemma of the bisexual floret not at all or scarcely bifid; lower glume membranous to coriaceous, with 2 delicate 

 keels; racemes almost sessile. 

 87A. Inflorescence a narrow silky panicle; spikelets awnless; lower glume membranous, without distinct keels; lodicules 



wanting; stamens 1-2 84. Imperata 



87B. Inflorescence a panicle or corymbose panicle, sometimes with a short axis; spikelets usually awned; lower glume 



herbaceous or rather coriaceous, with 2 keels; lodicules present; stamens usually 3 85. Miscanthus 



85B. Rachis of racemes articulate, disarticulating with the spikelets attached. 

 88A. Racemes in panicles; spikelets 1 -flowered. 



89A. Lower glume scarcely keeled at back; fertile lemma bifid 86. Spodiopogon 



89B. Lower glume with 2 keels at back; fertile lemma nearly entire 87. Saccharum 



88B. Racemes solitary or in corymbs. 



90A. Lower glume 2-keeled, flat or sulcata between the keels; upper glume awnless or short-awned. 



91A. Culms decumbent and much branched at base; leaf-blades lanceolate; lower glume glabrous, impressed or 



sulcate 88. Microstegium 



9 IB. Culms erect from the base, simple, usually not branched; leaf -blades elongate, linear; lower glume mosdy long- 

 hairy, flat 89. Eulalia 



90B. Lower glume convex; racemes solitary on culms; upper glume long-awned 90. Pogonatherum 



84B. Spikelets of two forms, the sessile bisexual, the pedicellate sterile, rarely bisexual. 

 92A. Racemes slender. 



93A. Inflorescence a panicle without bracts. 



94A. Internodes of the rachis without a hyaline center; glumes coriaceous; fertile lemma bifid 91. Sorghum 



94B. Internodes of the rachis with a hyaline line in the center; glumes chartaceous or slighdy coriaceous; fertile lemma 



not bifid 92. Bothriochloa 



93B. Inflorescence of 1 to many racemes arranged in a digitate corymb or of bracteate false panicles; internodes of rachis 

 without a hyaline line in the center. 

 95 A. Leaf -blades ovate, embracing the culm at base; fertile lemma entire or bidentulate at apex, awned from the 



back below the tip; racemes few to many, in fascicles 93. Arthraxon 



95B. Leaf-blades linear, narrow; fertile lemma awned from the tip or between the teeth. 



96A. Lower glume of the sessile spikelets 2-keeled or sulcate in front; callus of the spikelets obtuse, not elongate. 



97 A. Lowest pair of spikelets of one of the racemes alike, staminate, or neuter 94. Cymbopogon 



97B. Lowest pair of spikelets like the upper, one fertile and sessile, the other pedicellate, staminate, or reduced. 



95. Andropogon 



96B. Lower glume of sessile spikelets cylindric, terete, not keeled or sulcate; callus of sessile spikelets more or less 



elongate and acute at base; fertile lemma entire, with a thick awn at apex; 2 pairs of the spikelets at base 



of racemes alike, sterile, surrounding the upper spikelets as an involucre 96. Themeda 



92B. Racemes with a thick rachis. 



98A. Fertile lemma of sessile spikelets usually awned; racemes 2 (-3) (in ours), closely appressed to each other, usually 



pubescent 97. Ischaemum 



98B. Fertile lemmas awnless; racemes glabrous. 



