476 



PART III. THE CLASSIFICATION OF PLANTS 



generation is represented by two individuals, a male and a 

 female. 



The Male Individual is a prothallium developed from the 



cl 



FIG. 301. A Longitudinal section of the micropylar portion of the female prothallium of 

 Picea excelsa showing two archegonia ( x 100) : c neck of archegonitim ; cl canal-cell. 

 B Surf ace- view of unopened neck of an archegonium ( x 250). C Pollen-tube penetrating 

 to the oosphere through the neck of the archegonium ( x 250). (After Sirasburger.) 



microspore as described on p. 448. It consists of two or more 

 cells, one of which grows out into a pollen- tube (see Fig. 290). 



