362 BOTANICAL GAZETTE [DECEMBER 
Impelled by the meagerness of our knowledge, and by the 
want of accord among such papers as have been published on 
this subject, the writer two years ago began collecting and 
examining the sporangia of Lycopodium, Selaginella, and vari- 
‘ous ferns, to discover some of the forms most favorable for cyto- 
logical investigation. None was found so good as Osmunda. 
All three of the species occurring in the northern United States 
were collected, but only O. vegalis was found to be fixed and pre- 
served in a condition suitable for the purpose, and it alone has 
received any considerable attention. For want of time a full 
examination of the reduction divisions was not possible, and 
therefore attention was centered only upon such features as it 
was hoped might be followed in detail in the time at disposal. 
Accordingly in this paper only the origin, structure, and fate of 
the achromatic spindle are to be considered, together with such 
comments upon the changes in the chromatin as seem necessary 
for clearness. A more extensive account of the chromatic ele- 
ments of the spindle is reserved for a future occasion, after there 
has been opportunity for further study. 
The methods of fixation, embedding, and staining require a 
brief mention. As fixing agents, chromo-acetic acid (1 per cent. 
chromic acid, 0.75 per cent. acetic acid), and Flemming’s woake 
solution were employed. Chloroform was used as the medium of 
transfer to paraffin. The sections were cut 5 or 10M in thick- 
ness. To differentiate the fibrillar structures most clearly, = 
ous combinations of the following stains were tried: nigrosi, 
Delafield’s haematoxylin, erythrosin, iron-alum-haematoxy!im, 
acid fuchsin, methyl-green, iodine-green, safranin, gentian-violet, 
orange G. Of these stains the two combinations which saith 
yielded the best results are iodine-green and acid-fuchsin, - 
was found especially advantageous in dealing with the — 
elements, and safranin and gentian-violet, which was mos 
effective in bringing out the details of the achromatic figur 
The sporangia of Osmunda make their first app 
the latter part of summer, and continue their growth 10 ae 
autumn months. By mid autumn those of O. cinnamomed & 
