GROUP IV. PHANEROGAMJA : GYMNOSPEKM^E. 



B 



473 



FIG. 2P9. Later stages in the embryogeny of the sporophyte of Picea excelsa (after 

 Strasburger). A Optical section of young embryo borne on the end of the suspensors ( x 240) : 

 I? older embryo, with suspensor and embryonal tubes ; at this stage the growing-points of 

 primary root and stem are already differentiated : C half-grown embryo in surface-view : 

 D longitudinal section of a half-grown embryo : E surface-view of the apex of the shoot of 

 this embryo (x27): F longitudinal section of a fully developed embryo in a ripe seed; c 

 cotyledons; 7i hypoctyl; pi apex of the plerome in the root; cp root-cap ; m pith; op pro- 

 carnbial ring. 



