one : oie either stpamate ¢ or nenter, ; acne, 4 : 
8 
(hence these are named flowering glumes). Opposed to each flow- 
ering glume, with its back turned toward the rachilla, is (usually) 
a two-nerved, two-keeled bract or prophyllum (the palea), which 
frequently envelops the flower by its infolded edges. At the base 
of the flower, between it and its glume, are usually two very small 
hyaline scales pngset ; rarely there is a third lodicule between 
carp; fruit a caryopsis, rich in albumen. (In Sporobolus and Eleu- 
sine the thin pericarp is free from the seed.) 
There are about thirty-five hundred known species 
of grasses, varying in size from the moss-like Colean- 
thus of the North to the tree-like bamboos of the 
Tropics, which tower to the height of 100 feet or more, 
and ranging in distribution from Kerguelen Land on 
the south to the extreme limit of vegetation beyond 
the Arctic Circle. There is no order of plants more 
widely distributed, or existing under a greater diversity 
of soil and climate, and no other order presents sucha 
vast number of individual plants or is so Serer eat 
and directly useful to man. 
The characters employed in defining the tribes and 
genera are usually those presented by the spikelets or 
inflorescence. While the characters of the order are 
well defined and clearly separate it from all other 
families of plants, the establishment of the several 
subdivisions is very difficult, and in no case can be 
based upon a single character adda, but upon a combina- 
tion of them. There is no tribe or large genus which 
can be separated or defined absolutely from all others; 
there are always exceptions or intermediate forms 
connecting them. 
Series A —PANICACEE, 
Spikelets one rarely two-lowered: when two-flowered 
the second or terminal one is peak the first or lower 
