The Spermatogenesis of Polytrichum juniperinum. 
BY 
CHARLES E. ALLEN. 
With Plates XV and XVI. 
Introduction. 
I N a previous paper (Allen, 1912) I have followed the history of the 
successive generations of cells that occupy the interior of the antheridium 
of Poly trichum juniperinum down to the final division — that, namely, of the 
androcyte mother-cells. The present study is concerned with the meta- 
morphosis into antherozoids of the androcytes formed by this division. 
Certain of the observations here to be described have already been briefly 
reported (Allen, 1908, 1913, 1914). 
The methods used in this work were in the main those described in my 
paper of 1912. For the study of the fully developed antherozoids, the mass 
oozing from a mature antheridium into a drop of water was exposed for 
a minute or two to the fumes of osmic acid, or, in most cases, the slide 
bearing the drop was inverted over a small wide-mouthed bottle containing 
medium or strong Flemming’s solution. After fixation by this means, the 
slide was allowed to dry thoroughly, drying sometimes being hastened by 
a brief heating over a flame. Then the slide was immersed in the stain or 
stains to be used, thoroughly dried again, a drop of clove oil or other clear- 
ing agent was placed upon the material, and this was followed by Canada 
balsam. Dehydration of the stained preparations by alcohol was avoided 
after a few experiences, since it was found that the alcohol quickly extracts 
all colour from the cilia. Numerous stains and combinations of stains were 
used for the antherozoids so prepared ; the best results were obtained with 
acid fuchsin and iodine blue, safranin and gentian violet, and safranin and 
pyoktanin blue. 
Observations. 
A description has previously been given (Allen, 1912) of the small 
darkly staining body present in each young androcyte. This dense granule 
seems to be identical with that which behaved like a central body in the 
last preceding mitosis ; in the development of the androcyte into an 
[Annals of Botany, Vol. XXXI. No. CXXII. April, 1917.] 
