266 



BOTANY. 



endosperm is very often rudimentary or entirely wanting, 

 and the embryo is generally large. 



Sub-Class I. The Monocotyledons. Monocotyledonecs. 



503. The first leaves of the embryo are alternate ; hence 

 we say that they have one cotyledon. The venation of the 

 leaves is for the most part such that the veins run more or 

 less parallel to one another, and when they join each 

 other enclose four-sided spaces ; rarely, however, their veins 

 are irregularly distributed and form an irregular network. 



504. The germination of Monocotyledons may be illus- 

 trated by the Indian corn. Here the embryo lies partly 



Fio. 167.— Longitudinal section of the seed of Indian Corn, c, adherent 

 wall of the ovary; )i, remains of the style ; /s, base of the ovary (all the 

 remainder of the figure is the true seed); eg, ew, endosperm; sc, ss, coty- 

 ledon ; 6, its epidermis ; k, young leaves ; w, the main root ; w', roots 

 springing from the stem. Magnified 8 times. 



imbedded in one side of the large endosperm (Fig. 157.) 

 The first leaf of the young plant (the cotyledon, or scutel- 

 lum), sc, has its broad dorsal surface in contact with the 



