344 



MORPHOLOGY OF GYMNOSPERMS 



while in Podocarpus (69) only the nucleus of the body cell is said 

 to divide and all of the cytoplasm to be organized in connection with 

 one of the male nuclei as a male cell, leaving the other male nucleus 

 thrust out at its periphery. 



In Saxegothaea (149) pollen falls not only on the extruded and 

 broadly flaring tip of the nucellus, but sometimes also in the depression 

 around the o^nxle, and in this position pollen tubes develop and grow 

 over the tissues to the micropyle. It will be remembered that this 

 growth of pollen tubes to the micropyle from some distance outside 

 is one of the features of the araucarians (p. 283). 



FERTILIZATION 



i\mong the Taxaceae the tip of the pollen tube discharges all of 



its free contents into the 

 cytoplasm of the egg, in 

 the peripheral region of 

 which there may be found 

 both male cells or nuclei, 

 the stalk and tube nuclei, 

 and such prothallial nuclei 

 as may be in the tube. 

 All of these gradually 

 disappear except the 

 functioning male cell or 

 nucleus, although some- 

 times they may still be 

 distinguished in the early 

 stages of the proembryo. 

 In Cephalotaxus Foriunei 

 the non-functioning male 

 nucleus has been observed 

 (55) to divide amitotically, 

 producing as many as six 

 nuclei. In Phyllocladus 

 (174) the male cells are 



discharged outside the archegonium and pass between the separated 



neck cells. 



In Torreya calijornica (99), Torreya taxifolia (loi), Cephalo- 



FiG. 399. — Torreya taxifolia: fertilization; the 

 male nucleus is in contact with the egg nucleus; 

 the cytoplasm of the male cell is closely applied to 

 the egg nucleus; the functionless male cell and stalk 

 and tube nuclei are in the upper part of the egg; 

 August 12', 1904; X460. — ^After Coxjlter and 

 Land (ioi). 



