no GERMINATION OF THE GAMETOSPORE 



54. The Germination of the Gametospore and the Formation 

 of Seed. — The first indication of the germination and growth of 

 the gametospore is seen directly after fertilization. It Incomes 



Fig. 81. Germination of the gametospore of peppergrass, Lepidium: 

 ./, micropylar end of the embryo sac showing that the gametospore, g 

 (fertilized female gamete), has developed a cell wall and become attached 

 to the wall <»f the embryo sac. Compare Fig. 80, B, later stage in the 

 germination — t, embryo cell; s, suspensory cells; en, endosperm cells. 

 (', tlu- embryo cell ha-- formed two cells. /'. later stage. The embryo cell 

 by further division ha-, formed a spherical mass of cells, here shown in 

 ■ Note the appearance of an outer layer of cells, the epidermis, and 

 a central or stem region; .<. a few of the suspensory cells. /:, --till later 

 growth. Two growing regions, the cotyledons are appearing on the side 

 of the stem. /•". the micropylar end <>f the embryo sac, Bhowing the stage 

 of development where the parts of a small plant can be clearly recognized 

 otyledons; at, stem ending in r>">t. /-, t.. which is still attached the 

 suspensory cells; en, endosperm cells, now provided with walls, are being 

 absorbed as the plant or embryo enlarges. Note thai the embryo and 

 emhr slightly bent to the left This curvature is due to t! 



that the ovule in a great many plants 1 irved in its development 



with the result th.it the embi curved or U shaped form 



This f.irm of the ovule results in a complete bending over of the cotyle- 

 dons against the item, as shown in the nexl figure. 



