4o6 



GYMNOSPERMS 



then behave like the inner cortical ring cells, elongating and sur- 

 rounding the inner cortical ring cells, so that a transverse section 

 shows the primary suspensor in the middle, surrounded by two 

 cortical rings, the inner consisting of eight cells and the outer of 

 sixteen. Later, a third ring of cortical cells {x'm fig. 379 C) is cut ofT 

 and is added to the suspensor. And finally, even a fourth ring is cut 

 off and is added to the suspensor. 



Fig. 381. — Welwitschia mirabilis: same seedling as that in fig. 380, two years later 



The cells (C) undergo division, forming a cap, which is cast olT 

 later, as in Cephalotaxus. 



The stem, leaves, cotyledons and root are formed from the four 

 cells of the plate {c, in C of fig. 379). 



As the embryo grows down into the endosperm, the suspensor 

 becomes coiled and twisted in typical gymnosperm fashion and, 

 after the cap has been cast olT, the outer cells become dermatogen, 

 and the meristems of the root and shoot are organized. 



The seedling. — The seedling has two cotyledons and two leaves 

 (fig. 380). The cotyledons persist for two or three years and then 

 fall olT: the two leaves, at right angles to the cotyledons, persist 



