334 NATURAL SCIENCE. May. 



These points of agreement are, however, "so mixed up with striking 

 distinctions," that, so far, the author cannot claim to have found a 

 counterpart to the extraordinary facts recorded by Treub. " We 

 know nothing of an embryo-sac without antipodals, for they are present 

 and very conspicuous in the British Amentiferae. In Betula, Alnus, 

 and the Cupuliferse I have observed the fusing of the polar nuclei, and 

 in every genus the presence of synergidae and a naked egg-cell." 



Miss Benson, in continuing her work, hopes to find some clue to 

 the solution of the vexed problem of the homology of the antipodal 

 cells and the fusion of the polar nuclei of the embryo-sac. 



The four papers contained in the first instalment of volume viii. 

 of the Annals of Botany are somewhat diverse in origin. The first, by 

 Professor Campbell, hails from California, and includes the result 

 of some work on the development of Marattia Douglasii, the author 

 having been fortunate in finding a large number of very young plants, 

 and also the prothallia and embryos, while collecting in the Hawaiian 

 islands two years ago. Professor Campbell claims to have shed 

 more light on the position of the Marattiaceae and the origin of 

 Eusporangiatae from the Bryophytes. Points of resemblance between 

 the sexual generation of Marattia and the Liverwort Anthocevos are 

 adduced in support of this descent. 



In the next, Mr. H. H. Dixon describes his researches on the 

 fertilisation of the Scotch Fir, carried out in the Botanical Institute 

 of the Bonn University under Professor Strasburger's supervision. 

 It is found that in Piniis silvestris, as already shown for the Yew by 

 Belajeff, the nucleus of the pollen-tube is not the one efficient in fertili- 

 sation, as was formerly believed to be the case in Gymnosperms. 

 As Strasburger had previously demonstrated, in Angiosperms this 

 nucleus is asexual, the male sexual nucleus arising from one of the cells 

 originally behind the nucleus of the pollen-tube. In the Scotch Fir a 

 pair of cells borne on a stalk-cell are formed as the result of a few cell- 

 divisions on the side of the pollen-grain opposite the point from which 

 the tube emerges, and it is the nucleus of one cell of the pair which is 

 sexually functional. The author traces their separation from the stalk- 

 cell and passage down the tube, in which they are pursued and ultimately 

 passed by the nucleus of the stalk-cell, which then becomes indistin- 

 guishable from the original nucleus of the pollen-tube. All four nuclei 

 pass into the female cell, their path through which can often be traced 

 by the grains of starch which enter at the same time. Only one of 

 the pair of nuclei unites with the female nucleus, the other remaining 

 in the protoplasm with the two asexual nuclei from the pollen-tube. 

 In the Angiosperms, where a similar division into two similar sexual 

 cells occurs, Strasburger was able to observe in one case the fertilisa- 

 tion of an oosphere by the two nuclei, indicating that both cells are 

 truly sexual. It is suggested that the formation of two sexual cells 

 in Pinus came about when the branching of the pollen-tube, which 



