334 



2. Raceme! digitate or panicled. ;ill pedicellate. Rhachis 

 joints and pod hols with a median longitudinal trans- 

 lucent lino. Flowering glume pedicel-ltke, tapering 

 into an awn. (Subgenus Amphilophis.) 



3. Spikes with many pairs of spikelets (II .1. intcnnrdiiin 



I). Spikes imr to tlirc\ rarely four pairs ol spike- 



lets, the rhachis and branches capillary (5) X. micranthtu 



2. Racemes in panicles, frequently with few fertile spike- 

 lets. Rhachis joints without a translucent line. 

 ICmpty glume usually broadly lanceolate, finally in- 

 durated and shining': second glume awtilcss ; third 

 glume hyaline, 2-ncrved ; fourth entire or 2-fid, 

 awncd, rarely unawned. (Subgenus SOBQIIUM.) 

 3. Very coarse erect grasses. 



I. Annual; spikelets awncd or awnless ; 



cultivated only (7).l. sort/hum 



A. Perennial; spikelets awnless (G) A. halepentia 



3. Slender grasses. 



t. Awns 2.5 to 3 cm. long (9) A. baileyi 



I. Awns 1.5 cm. long or less, or wanting. 



5. Spikelets awnless (8) A. terratua iiiiirtus 



5. Spikelets awncd. 



(i. Spikelets 4 to 5 mm. long, 

 brown, shining, clothed 



with brown hairs (8) .1. aerrattu genuinua 



(I. Spikelets abOUt 2 nun. long, 

 pale or green ; panicles 



very delicate (10) .1. leptoa 



2. Racemes very many, in whorls upon slender pedicels; 

 these are arranged above one another, forming a 

 panicle. Sessile spikelets laterally or dorsally com- 

 pressed, awncd or not distinguished from the next 

 iChryaopogon) by the absence of a beard or rigid 

 hairs on the tips of the branchlets. ( Subgenus 

 Vktivbiua.) 



3. A stout erect tufted grass with aromatic roots, 

 with many-jointed spikes and muricate 

 glumes (11) .1. aquarrotua 



2. Racemes whorled, pedicellate on the capillary branches 

 of an erect panicle, usually reduced to one or two 

 terminal joints. Spikelets somewhat laterally com- 

 pressed. (Subgenus CHRY8OP0GON, ) 



3. Stem creeping, the flowering branches erect, the 



callus long, acicular (12) .1. cuHculatua 



1. Sessile spikelet of the lowest pair or of several of the lower 

 pains in each raceme, differing from the upper pairs in sex 

 or awns, or empty. (Series I!. Qeterozygi.) 



2. Racemes usually three to many, digitate, all pedicel- 

 late or all sessile, not subtended by a leaf sheath 

 Flowering glume usually stalk-like. (Subgenus 



1 Uc'llANTHII'M. I 



3. A slender erect grass with digitate, densely 



villous racemes (13). 1. Bericeua 



2. Racemes solitary or terminal upon the culm or its 

 branches. Spikelets imbricated, the first to fifth 

 pairs homogamous. Awns large, those of all the 

 spikelets with a pointed callus. (Subgenus Hktk- 



KOPOCtCIN I 



3. First glume flat dorsally (15) A, contortua 



3. First glume deeply channeled dorsally (11) A. triticeua 



2. Racemes in pairs, terminal upon the culm or its 

 branches, one sessile, always with 1 to 2 basal 

 homogamous pairs of staminate spikelets, the other 

 short pedicellcd, with or without homogamous pairs. 

 both together subtended by a sheathing leaf, fre- 

 quently arranged in a false panicle Interrupted by 

 loaves. (Subgenus Cymbopogon.) 



