CONIFERALES (PINACEAE) 



267 



maturation changes (51, 126). A similar case was reported for 

 Ginkgo by Tkeno. Such a nucleus appears to be ready for fertiliza- 

 tion. In Abies balsa mea (ygo) the ventral canal nucleus usually 

 enlarges somewhat and 

 persists until fertilization. 

 There are also cases in 

 which the wall separating 

 such a ventral nucleus from 

 the egg has been observed to 

 disappear, leaving two simi- 

 lar nuclei free in the cyto- 

 plasm of the egg (51); and 

 such equal nuclei have been 

 observed in contact (fig. 

 298), as if fusing (23, 44). 

 It seems reasonable to infer 

 that the ventral canal cell 

 is an abortive egg, which is 

 occasionallv organized as 

 an egg, and which in that 

 condition may be fertilized 

 (72), or may fuse with the 

 egg nucleus. The ventral 

 nucleus has also been ob- 

 served to divide (after the 

 fertilization of the egg), 

 either by amitosis (76) or 

 mitosis (72). 



The account of the 

 archegonium given above 

 applies in general outline 

 to all the Pinaceae, but 

 there are differences among the tribes that must be considered. 



Among the Abietineae the number of archegonia ranges from one 

 to seven, with two to five as the usual range, the smallest among 

 Pinaceae. The number of neck cells may be said to average about 

 eight, arranged in two tiers, with four cells in each tier; but there 



Fig. 298 — Finns Laricio: conjugation of 

 two nuclei which were described as male (w) 

 and female (/), but which are doubtless the 

 nuclei of the egg and ventral canal cell, as in fig. 

 297; both nuclei are in an early spirem stage; 

 it is interesting to note that the first record of 

 fertilization in gymnosperms (Picea, reported by 

 Strasburger 22) was very probably a case of 

 this kind; X500. — After Coulter (44). 



