190 POACE.E. 



d. Floral glume narrow, visually with a curved 

 sharp-jiointed hairy callus, and a stout, twisted 



and persistent awn 46 



d. Floral glume broad, with a very stout blunt 

 callus, and a weak terminal caducous tortuose 



awn 47 



d. Floral glume ventricose, with a short, stout, 

 flat, obliqne callus and a short, straight or 



curved awn 48 



c. Lodicules 2; awns slender, sometimes minute. 

 Falea membranons, closely enclosing the grain. 



Spikelets small 50 



c. Floral glume broad, deeply 2-toothed and with 

 palea only loosely enclosing the grain. . . .51 



b. Floral glume awnless 49 



b. Floral glume witli a straight terminal awn. Eachilla 



prolonged above the palea 51 



a. Spikelets in pairs, one containing a perfect flower, the 

 other staminate or sterile, forming the spikelike pani- 

 cle 53 



a. The spikelets containing perfect flowers surrounded at 

 the base by numerous sterile (and a few staminate) spike- 

 lets which are reduced to bristles or bracts 54 



B. Floral glnme usually hyaline or membranous at maturity, not 

 so firm as the empty glumes; grain loosely or not at all en- 

 closed (a) 



a. Empty glumes none ; spikelets in umbel-like clusters, 



paniculate; stamens 2, plants very small 58 



a. Empty glumes present (b) 



b. Palea '' -nerved ; stamen 1 ; floral glume raised on a 



distinct naked callus, panicle loose 65 



b. Palea usually none, if present small and keeled; 

 spikelets in a dense spikelike panicle or head ; floral 



glume usually with a bent dorsal awn 57 



b. I'alea usually present, 2-nerved (c) 



