Fig. 312. — Araiicaria cunninghamii: development of the male gamctophyte; A, uni- 

 nucleate microspore, with nucleus surrounded by starch grains; the exine and intine of 

 about equal thickness; li, the first two prothallial cells; C, the first prothallial cell has di- 

 vided anticlinally and the starch grains arc very large; the intine is much thicker than the 

 exine; D, two primary prothallial cells have divided and the generative cell {g) and tube 

 cell (/) have been formed; E, the generative cell has divided into a stalk cell (s) and body 

 cell {h) ; F, the body cell has enlarged, the walls of the prothallial cells have broken down, 

 leaving the nuclei free; s is probably the nucleus of the stalk cell and /, the tube nucleus; 

 G, the body cell is easily recognizable, / is the tube nucleus, and s may be the stalk nu- 

 cleus; X950. 



