394 Brown: Regeneration in Phegopteris polypodioides 



the cells of both the upper and lower surfaces of the cellular mass, 

 although the majority came from the upper surface cells. Their 



Figs. 1-3. Stages in the regeneration of the young leaf of a sporophyte of 

 Phegopteris polypodioides Fee, x 550. R, rhizoids; LS, leaf of sporophyte; CM, cellular 

 mass; IS, intermediate structure; MR, midrib; T, tracheids; S, stomata; ist L, first 

 leaf; 2d L, second leaf; 3d L, third leaf; 4th L, fourth leaf. 



development began at about the same time as that of the inter- 

 mediate structures. 



After a number of rhizoids had been formed from the surface 

 cells of the mass, normal leaves began to develop. The first and 

 second of the four leaves appeared almost simultaneously and 



