3o6 



THE EMBRYO 



[CH. 



Y— , 



Fig. 290. Botrychium obliqwim. First stages in the embryogeny. Before 

 the, first segmentation the zygote grows into an elongated tube, cut 

 off later as the suspensor, which burrows its way irregularly into the 

 tissue of the prothallus. ( x 150.) From sections lent by H. L. Lyon. 



Fig. 291. Embryo oi Botrychium 

 obliqitum in transverse section 

 at the level of the stem-apex 

 {ap). ^-i <r= cotyledon; j = sus- 

 pensor ; 7;^ = vascular bundle. 

 (From a preparation lent by 

 H. L. Lyon.) 



Fig. 292. Botrychium Ltinaria, L. 36 = a fertilised 

 archegonium ; 37=zygote, showing the first seg- 

 mentation; 38 = embryo of four cells; 39, 40 = em- 

 bryos cut in direction of the axis of the archegonium ; 

 42 = an embryo breaking out of the prothallus; 

 36 — 40x225; 42x150. (After Bruchmann.) 



