THE AGRICULTURAL GRA86ES OF THE UNITED STATES. 13 



the midntri'f or midrib, extendiug" to the poiut of tlie leaf, and numerous 

 fine lines or nerves on each side running parallel to each other, and not 

 connected by transverse nerves and not giving oft' branches as in the 

 higher plants. These leaves are in some species rough, in others 

 smooth, hairy, or downy, tSrc. The agricultural value of a grass depends 

 mainly upon the quantity, quality, size, and nutritive properties of the 

 leaves. 



(4.) The flowers : The flowers of the grasses are generally at the end. 

 of the stem or the side branches, sometimes very few in number, some- 

 times in great abundance, sometimes in a close spile, and sometimes in 

 R panicle, with many spreading branches or rays. The flowers may be 

 single on the branches or on the 2)edicels, or they may be variously clus- 

 tered. In the common red-top {Agrostis alha or A. vulgaris), there is a 

 single flower at the end of each of the small branchlets of the panicle. 

 Each of these flowers is inclosed by a pair of small leaf-like scales or 

 chafl', called the outer or empty glumes. The flower consists of (1) the 

 essential organs and (2) the envelopes. The essential organs are the 

 stamens and pistils, which may readily be seen when the grass is in 

 bloom. The stamens, of which there are usually three in each flower, 

 consist of the anther and filament, the anther being the small organ 

 which contains the pollen or dust which fertilizes the pistil or female 

 organ, and the filament being the thread-like stem on which the anthers 

 are borne. 



The pistil is the central organ of the flower, and consists of three 

 parts, the ovary, the style, and the stigmas. In most of the grasses the 

 styles are divided into two branches which have a handsome plumose 

 appearance. The stigmas are the delicate paris at the extremity of 

 these branches which receive the pollen for the fertilization of the flower, 

 and the ovary is that part at the base which contains the future seed. 



The envelopes of the flower are usually two leaf-like scales or husks in- 

 closing between them the stamens a.ud pistil ; these scales face each other, 

 one being a very little higher on the axis than the other, and also 

 usually smnller and more delicate in texture. This smaller scale is called 

 the palet ; the other larger and usually coarser one is called the Hou^er- 

 ing glume ; its edges generally overlap and partly inclose the palet. 



The flower constituted as above described, together with the pair of 

 outer or empty glumes at the base, form what is called a spilelet. In 

 many cases, however, there, are two three, or more flowers, sometimes 

 even ten to twenty, in one spikelet, in which case they are arranged 

 alternately on opposite sides of the axis, one above the other, with a 

 pair of empty or outer glumes at the base of the cluster. Such may be 

 seen in the blue grass (Poa pratensis), fescue grass (Festuca), and many 

 others. 



There are innumerable modifications of these floral organs, and upon 

 the differences which exist in them the distinction of genera and species 

 are based. In some cases the glumes are entire in outline, in some they 



