THE SPERMAPHYTES. 



221 



range from the inconspicuous, unattractive forms borne 

 by the grasses to the conspicuous and beautiful ones pro- 

 duced by the orchids. 



There are about 18,000 species of Monocotyledons; these 

 are variously arranged in groups, series, and orders by 

 different botanists. The Monocotyledons include some of 

 the most important economic and some of the most beauti- 

 ful ornamental plants. Our present limits will permit of 

 the study of but a single type. 



INDIAN CORN. PRACTICAL STUDIES. 



1. Examine an entire plant of 

 when it is in the flower. The 

 male flowers are borne in two- 

 flowered spikelets in spikes at the 

 top of the stem, constituting what 

 is called the tassel. The female 

 flowers are borne in dense spikes 

 of many rows on short branches 

 that grow in the axils of the 

 leaves. Each filament of the silk 

 is an elongated style. The pollen 

 grains, falling or blown from the 

 male flowers, extend their tubes 

 through these long styles, fertilize 

 the contents of the embryo sac at 

 the base of the pistil, and kernels of 

 Corn develop. Examine the leaves 

 for their arrangement and vena- 

 tion. Does the plant send down 

 a single taproot, or does it lose it- 

 self in branches ? Where do the 

 secondary roots originate? Are 

 there roots of a still higher order ? 



Indian Corn, Zea mays, 



FIG. 140. Longitudinal sec- 

 tion of fruit of Zea mays, 

 a, rind of the fruit ; n, ap- 

 pendage of the stigma ; fs, 

 base of the fruit; eg, yel- 

 lowish, firm part of the 

 endosperm ; ew, its white 

 and looser part ; sc, the 

 scutellum of the embryo ; 

 ss, its tip; e, its epithe- 

 lium; k, the plumule; w 

 (below) , the primary root ; 

 ws, rootsheath ; w (above), 

 secondary roots springing 

 from the first internode of 

 the primary stem, st. Mag- 

 - nified. (After Goebel.) 



