SPERMATOPHYTA 



357 



with free-nuclear division followed by the formation of compact, small- 

 celled, nutritive issue (Fig. 306). The archegonia, usually numbering 

 two or three, appear in the micropylar region. They have many tiers of 

 neck cells. A ventral canal nucleus is cut off but a wall does not separate 

 it from the egg nucleus. 



Fig. 304. Strobili of Gnetum latifolium. A, leafy branch with staminate strobili, natural 

 size; B, part of staminate strobilus, enlarged; C, an expanded staminate "flower," X5; D, 

 branches with ovulate strobili, natural size; E, part of ovulate strobilus, enlarged. {After 

 Bliime.) 



In WelwitscMa the development of the female gametophyte proceeds as 

 far as the formation of walls, but this is incomplete and the cells are multi- 

 nucleate. Nuclear fusions are said then to occur in most of the cells until 

 they become uninucleate. No archegonia are formed. The cells in the 

 micropylar region are multinucleate and become free eggs, sending out 

 tubes into which their nuclei pass. These tubes penetrate the nucellus, 



