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Tripe VIII.—AGROSTIDEX. 
Spikelets all hermaphrodite, 1-flowered with 3 glumes, the first 
palea into a naked or plumose bristle. Palea two-nerved (one- 
nerved in Cinna), nerveless, or (in some Agrostis species) wanting. 
This is, next to the Festucew, the largest tribe in the 
order, numbering 700 species arranged in 46 genera. 
The species are distributed throughout all the tem- 
perate and colder regions of the world and many occur 
within the Tropics. The genus Agrostis, from which 
the tribe derives its name and from which comes the 
word ‘‘agrostologist,” has about one hundred species, 
found in all parts of the world, especially in the north 
temperate zone. Some of our most important meadow 
grasses—notably Herd’s-grass and timothy—belong to 
this tribe. 
KEY TO THE GENERA OF THE AGROSTIDE2. 
— 
. Flowering glumes awned or mucronate-pointed -......--.- 2 
1. Flowering glumes awnless 19 
2. First empty glume with two to three awns, sate ri a 
spike-like panicle . Lycurvs 
2. First empty glume with a single awn or awnless 5 
3. Awn of the flowering glume terminal or from between the 
teeth of the bifid apex + 
3. Awns dorsal 13 
4. Awns 3-branched or trifid, the lateral divisions sometimes 
39 
very short : . ARISTIDA 
4. Awns simple or unbranched 5 
5. Awns articulate with the apex of the flowering glume ...-- 6 
5. Awns not articulate with the glume 8 
6. Awns usually long, geniculate and twisted below, persistent or 
but tardily separating from the narrow and rigid flowering 
si which is tightly rolled around the grain in fruit; 
callus acute 40. Sripa 
. Awns short, caducous or falling off soon after flowering - - --- 7 
