28o 



MORPHOLOGY OF GYMNOSPERMS 



gonial complex. Among the Abietineae, however, only one of the 

 two male cells produced by a body cell can function, and this fact seems 



330 



Figs. 328-331. — Pollen tube structiires of Cupressineae: figs. 328, 329, Thuja 

 occidentalis, fig. 328 showing the body cell with stalk and tube nuclei in advance, and 

 fig. 329 the two male cells; Xs6o; after Land (72); fig. 330, Cupressus Govenimm, 

 end of pollen tube with complex of male cells, the stalk and tube nuclei in advance; 

 X3S0; after JuEL (91); fig. 331, Libocedrus decurrens, the two male cells; after Law- 

 son (131). 



to be related to the tendency to eliminate one of the male cells. In 

 Tsuga canadensis (60) one male cell becomes larger than the other. 



