11 



This is, uext to the Festucece, the largest tribe in the 

 order, uumberiiig seven hundred species arranged in 

 forty-six genera. Tlie species are distributed through- 

 out all the temperate 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. 



Aristida Linn.* Sporobolus R. Br.* 



StipaLinn.* Epicaiiipes Presl.* 



Oryzopsis Michx.* Polypogon Desf. 



Eriofoma.** Limnodia L. H. Dewey.* 



Milium Liun.* (Thurberia Benth.) 



Muhlenbergia Schreb.* Arctagrostis Griseb. 



Brachyelytrum Beanv."* CinnaLiun.* 



Lycurus Kuuth. Agrostis Linn.* 



Pereilema Pre.sl. Gastridiiim Beauv. 



Heleochloa Host.* Calamagrostis Roth.* 



Plileniu Linn.* Ammopbila Host.* 



Alopeciirus Linn.* Calamovilfa Scribn.* 



Coleanthus Seid. Apera Adaus. 



Phippsia R. Br.* Lagurus Linn. 



Tribe IX. — Avenecc. 



Spikelets two- to several-flowered ; outer empty glumes usually 

 longer than the first floral glume; one or more of the floral 

 glumes awned on the back or from between the teeth of the bifid 

 apex ; awn usually twisted or geniculate ; the callus, and usually 

 the Joints of the rachilla, hairy. 



A tribe comprising twenty-three genera and over 

 three hundred species widely distributed in the tem- 

 perate regions of both the Old and the New World, 

 particularly abundant in South Africa and Australia, 

 a few extending beyond the arctic circle. 



