NOTES AND LITERATURE 



809 



being the generative cell, which afterward divides into a stalk and 

 body cell. The latter produces two similar male cells and this seems 

 to be the rule in the Cupressineae. No sterile prothallial cells such 

 as occur in the Abietineae and Cycas have been found in any Cupressi- 

 neae. The other genera, in which a similar division was observed, 

 were Cupressus, Chamaecyparis, Thuja, Cryptomeria and Taxodium. 

 Both of the latter, according to Lawson, show close affinity with the 

 Cupressineae, with which, however, they are not usually associated. 

 Libocedrus, in the history of the male gametophyte, approaches most 

 nearly to Thuja. 



Two megaspore mother cells are usually present and from each of 

 these four megaspores arise. Only one of the latter, hoAvever, develops 

 a prothallium, the others being apparently destroyed by its further 

 growth. The megaspore in its earlier stages of growth contains 

 several vacuoles which ultimately fuse into a single large central one 

 surrounded by a parietal layer of cytoplasm. In the latter are many 

 free nuclei as in other conifers. The development of the cellular 

 tissue from the multinucleate protoplasmic layer seems to closely 

 resemble what has been dascribed in various other conifers and seems 

 to offer no marked peculiarities. 



The archegonia in Libocedrus as in Thuja and Juiii])('nis are in a 

 coiufMct group aiul number from ten to fifteen. Thrrv iivo five or six 

 neck colls niid as in other Cupressineae and in (\>i)li;ilot.t\iis. 

 ventral canal cell is represented only by the nucleus, tlici-c hcin^' no 

 proper vcMilral canal ci^ll. The whole grou]-) of a rclici:-onia is -sur- 

 rounded by a layer of jacket cells, bul no direct protoplasmic connec- 

 tion could be shown between the latter and the eiru' cell and it is 



through thv cell walls. 



tincae, but more so than (\>i)lialota\u>. Tlin .- excellent plates com- 

 plete the paper. 



The Araucariaceae have naturally recei\(-<l le^s attention than the 



