1 



1907] YOUNG— MALE GAMETOPIIYTE OF DACRYDIUM in 



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but some had tubes twice the length of the spore. In these there 

 appeared always the conspicuous body cell and six free nuclei. Among 

 the latter one could sometimes recognize the tube and generative 

 daughter nuclei by their position or appearance, but sometimes they 

 were quite indistinguishable. In several cases one, presumably 

 the tube nucleus, had entered the tube and the others were about to 

 follow it {figs. 12 y Jj). 



From the number of free nuclei, it is fair to infer that in D, laxi- 

 jolhim^ as in Z). ctipressimim^ the first prothallial cell has dividcch 

 Another possible explanation would be the division of the body cell, 



but the latest stages in D. Bidwillii, in which the shedding of the 

 pollen had begun, could not have been much earlier tlian that of the 

 ungerminated pollen grains in the micropyles,* and there was no 

 evidence of such a division in cither of these. In several cases, too, 

 the position of two free nuclei side by side against the lower wall 

 suggested their origin from the first prothallial cell. 



The latest stages found were in D. intermedium collected January 

 31. The tubes had penetrated the nucellus to some distance, and 

 free nuclei were seen in them, but there was no evidence of any 

 further divisions. The body cell, still undivided, remained alone 

 in the cavity of the pollen grain. It seemed probable that it would have 

 divided and given rise directly to two sperms, as in other conifers, 

 but there might be other divisions previous to sperm formation. It is 

 hoped that in the near future material can be secured and the life- 

 history completed. 



DISCUSSION 



The striking facts about the male gametophytc are (i) the multi- 

 plication of prothallial cells and (2) the transverse division of the 

 generative cell. The development in Dacr)'dium agrees rather 

 closely with that described by Coker for Podocarpus, except that 

 there is no sign of degeneration of any of the cells, and the division 

 of the generative cell in Podocarpus was not obscrv-ed. In the light 

 of what we now know about Podocarpincae, one can hardly study 

 Lopriorf/s drawings of Araucaria without agreeing with Chambp:r- 

 LAix's view. The mode of origin of the cell complex at once suggests 

 the prothallial cells of other conifers, and the large nucleus with its 

 cytoplasmic sheath looks too much like a body cell to be called vegeta- 



