CONIFERALES 



303 



which the mother-cell was proved to be hypodermal in origin is 

 Larix (fig. 307 Z)). 



The cells surrounding the mother-cell soon become modified, and 

 furnish nutrition to it as it increases rapidly in size (fig. 308). These 

 cells constitute the "spongy" tissue, and furnish nutrition, not only 



Fig. 308. — Finns laricio: megaspore mother-cell with nucleus in prophase of reduc- 

 tion division. Surrounding it are modified cells, called the "spongy tissue," which fur- 

 nish nutrition not only to the mother-cell, but to later stages; X500. — From Coulter 

 and Chamberlain, Morphology of Gymnosperms^^^ (University of Chicago Press). 



to the growing megaspore, but even through early stages of the fe- 

 male gametophyte. They are finally entirely absorbed. 



Occasionally, the megaspore fails to develop. In such cases, the 

 spongy tissue may become very active and its cells may look like 

 megaspores, or like early cellular stages of a female gametophyte. 

 This behavior is rather frequent in Pinus contorta (fig. 309), 



When the mother-cell is developing normally, the tissue around it 



