236 FAUM GRASSES OF THE UNITED STATES 

 THE GRASS FLOWER 



The seed-head of the true grasses is of two general 

 patterns. One is seen in the head of wheat, barley, 

 timothy, etc. This form of seed-head is called a spike 

 (see Fig. 50) . Examination of a head of wheat shows 

 that it consists of a number of "meshes " arranged in 

 two rows on opposite sides of a central stem. These 

 meshes consist of from three to five flowers each, 

 arranged in a compadl cluster called a spikelet (Fig. 

 51). In the timothj- head the spikelets are not 

 arranged in two opposite rows, but are scattered over 

 an enlarged continuation of the stem. 



A very different pattern of seed-head is found in 

 oats, Kentucky- blue-grass, and the like. The flowers 

 of these are grouped in spikelets, but the spikelets are 

 not arranged on a single stem. The}^ are found at the 

 tips of the many branches of the stem. This much- 

 branched form of seed-head is called 2i panicle (Fig. 52). 



Let us now examine more closely one of the small 

 spikelets found at the tip of a branch of a blue-grass 

 panicle. Fig. 51 shows one of these spikelets verj- 

 much enlarged. Apparently it consists of seven parts 

 verA- much alike. In reality the two lower di\nsions 

 are merely two emptj' chaff-like lea%'es. The remain- 

 ing five parts are complete flowers, having enclosed 

 within each the organs that are seen in the expanded 

 flower shown in Fig. 53. The names of these parts of 

 a spikelet are shown in Fig. 5 1 . The flowers of the 

 true grasses are called florets. 



The parts of a single floret are well shown in Fig. 

 53. First, there is the leaf-like floral glume, verj- much 

 like the empty glume at the base of the spikelet. 



