﻿l86 BOTANICAL GAZETTE [march 



i» 



protuberance) becomes completely separated from the egg cell, 

 it is difficult to see how a wall such as usually separates the 



ventral canal cell from the eersf could be formed after the achro- 



matic figure has disappeared. It seems more likely that here, 

 as in Zamia, the disorganizing protuberance might have been 

 taken for a cell, and Ikeno himself in a brief note at the close 

 of his paper on Ginkgo (lo) admits that the wall may be lack 

 ing. In Ginkgo, which in so many features resembles the Cyca- 

 dales, a definite ventral canal, cell is separated from the ^gg by 

 a wall, as figured by Strasburger (i) , and the details of the 

 mitosis are described by Ikeno (lo), who figures a conspicuous 

 cell plate at the telophase of division. 



The Coniferales present some variation in the formation of 

 the ventral canal cell ; in most of the cases reported a definite 

 wall being formed between the two nuclei, but in Cephalotaxus 

 (Arnoldi, 9), in Taxodium and Podocarpus (Coker, 12), and in 

 Thuja (Land, 13), no wall is formed. Arnoldi's statement that 

 the ventral canal cell is lacking in the Cupresseae certainly does 

 not hold for the group, and it is doubtful whether such a cell or 

 at least a nucleus representing it is absent in any gymnosperm. 

 It would be of interest to know whether in any of the Cycadales 

 a definite wall is formed between the nuclei of the ^%% and ven- 

 tral canal cell. Since such a w^all is uniformly present in the 

 bryophytes and pteridophytes, its absence among the Cycadales 

 would have to be regarded as a case of suppression. 



Our preparations of the fertilization stages in Zamia merely 

 confirm the very full account recently published by Webber (n)- 

 The immense size of the fertilized ^gg of Zamia is a matter 

 of surprise to any who are not familiar with the archegonia of 

 Cycadales. The fertilized egg is usually 3™"^ in length, and its 

 nucleus is plainly visible to the naked eye, often reaching a 

 length of 1000//., as shown \nfig.j, which show^s the actual size 

 of the upper portion of the gametophyte with two archegonia. 



After fertilization there is a period of free nuclear division. 

 These divisions are simultaneous [fig, 4) and follow one another 

 with such rapidity that the nuclei become smaller at each suc- 

 cessive division. The first nuclear division was not found in 



