236 FARM 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 ahead 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 compact cluster called a spikelet (Fig. 

 51). In the timothy 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. They are found at the 

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

 branched form of seed-head is called a 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 very 

 much enlarged. Apparently it consists of seven parts 

 very much alike. In reality the two lower divisions 

 are merely two empty chaff-like leaves. 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. 51. 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, very much 

 like the empty glume at the base of the spikelet. 



