96 BOTANICAL GAZETTE [august 



of Dioon a number of very minute "black granules" which he was 

 inclined to believe originate within the nucleus. Very soon two 

 undoubted blepharoplasts are present, and are apparently formed 



of two of the original black granules. Very 



enlargement 



mitosis 



form the cilia-bearing band as in other cycads. In an earlier 



homolo 



centrosome 



From 



two general views concerning the morphological nature of the 



gymno 



sperms 



(i) The blepharoplast represents a centrosome (Hirase 



GuiGNARD, SCHAFFNER, WlLSON 



asmic 



material but not a centrosome (Strasburger, Webber, Shaw, 



Woodburn). 



spermatogene 



merits 



of these two views, and it is with particular reference to this prob- 

 lem that the results are given consideration in the following pages. 



Materials and methods 



Spores were collected in Chicago, May 15, 1911, and sown upon 

 clean sand watered from below. These cultures were kept under 

 ground glass in the greenhouse of the Hull Botanical Laboratory. 

 In five weeks, a somewhat longer time than is usually necessary, 

 sperms were swimming in large numbers. 



Several killing fluids and stains were used. By far the most 

 satisfactory results were obtained with the iron-hematoxylin of 

 Haidenhain after a killing fluid made up as follows: bichromate of 

 potash 2.5 gm., bichloride of mercury 5 gm., water 90 CC., freshly 

 distilled neutral formalin 



10 cc. 



Description 



theridium 



that it occurs in two forms, developing in some cases like the anthe- 

 ridium of the eusporangiate DteridoDhvtes. and in others from a 



