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2. Racemes digitate or panicied, all pedicellate. Rhachis 
joints and pedicels with a median longitudinal trans- 
lucent line. Flowering glume pedicel-like, tapering 
into an awn. (Subgenus Amphii.ophis.) 
3. Spikes with many pairs of spikelets (4) A. 
3. Spikes one to three, rarely four pairs of spike- 
lets, the rhachis and branches capillary (5) A. 
2. Racemes in panicles, frequently with few fertile spike- 
lets. Rhachis joints without a translucent line. 
Empty glume usually broadly lanceolate, finally in- 
durated and shining ; second glume awnless ; third 
glume hyaline, 2-nerved : fourth entire or 2-fid, 
awned, rarely unawned. (Subgenus Soroiium.) 
3. Very coarse erect grasses. 
4. Annual : spikelets awned or awnless ; 
cultivated only (1) A. 
4. Perennial ; spikelets awnless (6) A. 
3. Slender grasses. 
4. Awns 2.5 to 3 cm. long (9) A. 
4. Awns 1.5 cm. long or less, or wanting. 
5. Spikelets awnless (8) A. 
5. Spikelets awned. 
6. Spikelets 4 to 5 mm. long, 
brown, shining, clothed 
with brown hairs (8) A. 
6. Spikelets about 2 mm. long, 
pale or green ; panicles 
very delicate (10) A. 
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, awned or not distinguished from the next 
(Clirysopogon) by the absence of a beard or rigid 
hairs on the tips of the branchlets. (Subgenus 
Vetivbkia.) 
3. A stout erect tufted grass with aromatic roots, 
with many-jointed spikes and muricate 
glumes (11) A. 
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 Chrysopogon. ) 
3. Stem creeping, the flowering branches erect, the 
callus long, acicular (12) A. 
1. Sessile spikelet of the lowest pair or of several of the lower 
pairs in each raceme, differing from the upper pairs in sex 
or awns, or empty. (Series B. Heterozygi.) 
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 
Dichanthium. ) 
3. A slender erect grass with digitate, densely 
villous racemes (13) A. 
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 Hbte- 
ROPOGON. ) 
3. First glume flat dorsally (15) A. 
3. First glume deeply channeled dorsally (14) A. 
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 pedicelled, with or without homogamous pairs, 
both together subtended by a sheathing leaf, fre- 
quently arranged in a false panicle interrupted by 
leaves, (Subgenus Cymbopogon.) 
intermedins 
micraiithus 
sorghum 
halepensis 
haileyi 
serratus nitidus 
serratus genuinus 
leptos 
squarrosus 
acicutatus 
scriccus 
cotitortns 
triliceus 
