AXDltOPOUONE.E. 21 



Stamens 3, rarely 2 or 1. Styles free. Stigmas plumose. Embryo 

 n(!arly half as large as the unfurrowed obcompressed grain. 



A. Spikelets homogamous, paniculate, rarely spicate, joints of the 

 racliis usually hairy, not much thickened, nor excavated for the 

 reception of the spikelets. 



a. Axis of the racemes continuous, spikelets in pairs, rarely in 

 threes. 



b. Racemes in a spikelike panicle, spikelets awnless. 5. (73) 

 b. Racemes in broad panicles. Spikelets usually awned. G. (74) 



a. Axis of racemes articulate. Spikelets 2-flowered, the spikes 

 or racemes paniculate, main axis elongated. 



b. Spikelets awnless 7. (75) 



b. Spikelets av.ned 8. (7<3) 



B. Axis of the spikes articulate, somewhat thickened and excavated 

 for receiving tiie spikelets; fertile glumes awnless. 



a. First empty glume of the perfect s[)ikelet flattened or con- 

 vex !i. (84, 88) 



a. First empty glume of the perfect spikelet hard and globular, 

 externally pitted 10. (s7) 



C. Spikelets heterogamous. the sessile perfect (rarely pistillate), 

 the pedicellate staminate, neuter or rudimentary (\n 7'ntrfii/po- 

 go)i one spikelet is pedicellate, the other subsessilc). 



a. Secondary s])ikelets 2-flowered, sessile, awned. pedicellate 

 si)ikelets flower-bearing; racemes 3-lG. digitate . 11. (!>1) 

 a. Sessile or subsessile spikelets 1-flowered. Horal gluine of the 

 l)e(licellate spikelets awidess. (n) 



n. Axis of the racenu'sim perfectly articulate, not brittle, 

 spikelets all more or less pedicellate . . . . 12. (!I2) 

 n. Axis of racemes distinctly articulate; spikelets both 

 sessile and pedicellate, (o) 



o. First empty glunu' with abalsam-bearing line along 



the nerves ; racemes solitary ; spikelet awnless. I '.]. (s;{) 



0. First empty glume ^\itliOut a balsam-bearing line 



along the nerve->, racemes in i)airs, often subtende<l by 



a leaf-slu'ath or bract 14. ('.•4) 



6. (73). IMPERATA (yrill. I'l. Rar. Ic. 2. 2*5, L . 11 (17!)2). 



