CONIFERALES 97 



it, both walls being intact. At this time similar changes occur in 

 the contents of both nuclei, and the spindle of the first segmenta- 

 tion begins to organize while the two nuclei are still distinct. 

 Blackman claims that no resting ferti- 

 lized nucleus is ever formed, although in 

 all other known plants the male and fe- 

 male nuclei fuse while in the resting con- 

 dition and form a definite resting ferti- 

 lized nucleus. Chamberlain confirms 

 this so far as to state that the two nuclei ' 

 are in the spirem stage after the male 

 nucleus has entered the female nucleus 

 (Fig. 75). Woycicki *'^ has also ob- 

 served in Larix Dahurica that in some 

 cases after the coalescence of the two 

 nuclei two separate chromatin groups 

 are to be distinguished, one of which he -^'"'- 75.— /'iaws Larido, the 

 would regard as the male, and the other tTetltt^rpt 

 the female group. Such behavior finds rem stage within the lim- 

 its parallel among animals, as in As- its of the female nucleus ; 



■ * 1. J. X -\ . (■ " S""- — After Chameee- 



cans," but not among plants, so far as j_^jj, 

 known. The process of fusion is exceed- 

 ingly slow, according to Blackman beginning when the male and 

 female nuclei begin to react upon one another, and closing 

 when the half chromosomes, derived from the male and female 

 nuclei respectively, fuse at the poles of the first segmentation 

 spindle. See Appendix. 



Some minor deviations from this account of Blackman, given 

 for Pinus, have been observed by Coker *^ in Taxodium dis- 

 tichum, and by Jager *" in Taxus baccata. lii the former the 

 two nuclei come in contact near the upper end of the egg and 

 travel together toward the base, not fusing completely till the 



* " In Van Beneden's epoch-making work on Ascaris it was shown not only 

 that the nuclei do not fuse, but that they give rise to two independent groups 

 of chromosomes which separately enter the equatorial plate and whose descend- 

 ants pass separately into the daughter nuclei. Later observations have given 

 the strongest reason to believe that, as far as the chromatin is concerned, a 

 true fusion of the nuclei never takes place during fertilization, and that the 

 paternal and maternal chromatin may remain separate and distinct in the 

 later stages of developmeiit — possibly throughout life." — Wilson's The Cell in 

 Development and Inheritance, second edition, p. 304 



