O YMNOSPERM^E. 



405 



the first root of the new plant, and eventually gives rise to 

 its whole root sys- 

 tem. The cotyle- 

 dons having thus 

 far been in contact 

 with the e n d o - 

 sperm, which fur- 

 nished them with 

 nourishment, now 

 elongate and push 

 out their bases, and 

 in some cases even- 

 tually withdraw 

 themselves entirely 

 from the seed coat 

 (Fig. 300, ///.). 

 The apex of the 

 axis (plumule) be- 

 gins a rapid growth, 

 which gives rise to 

 a leafy stem resem- 

 bling that of the 

 parent plant, al- 

 though usually 

 somewhat simpler. 



515. The tis- 

 sues of the Gymno- 

 sperms are individ- 

 ually but little high- 

 er than those of the 

 Pteridophytes, but 

 in the mode of their 

 aggregation they 

 present great and 

 important differ- 

 ences, in this latter 

 respect bearing a 

 close resemblance to 

 the tissues of the 

 Dicotyledons among 



Pie. 300. Seeds of Pinu* Pinea in different stages of 

 germination. /., ripe seed in longitudinal section ; , 

 the seed coat ; e, endosperm ; w, the hypncotyledonary 

 axis of embryo ; c, cotyledons ; y, the micropylar end 

 of the seed, with the root of the embryo directed to- 

 wards it. //., //., four views of the beginning of ger- 

 mination ; A, external view ; B, with half of the seed 

 coat removed ; (7, in longitudinal section ; Z>, in 

 transverse section ; , seed coat ; r, red membrane lin- 

 ing the seed coat ; e, endosperm ; c, cotyledons ; w, 

 root ; as, ruptured embryo sac. ///., germination com- 

 plete, the cotyledons, c, unfolding, and the hypoctyle- 

 donary stem, he, elongating ; w, the main root, devel- 

 oping lateral roots, w'. After Sachs. 



the Angiosperms. The three tissue sys- 



