130 
Charles E. Allen 
The terms here suggested (androcyte, androcyte mother cell and 
androgone) are of course equally applicable to the corresponding cell 
generations not only in bryophytes, but also in other plants which 
produce differentiated male gametes. 
Material and Methods. 
Male heads of Polytrichum juniperinum have been collected for the 
purpose of the present study at intervals since May 1906. After removing 
most of the leaves, the heads were fixed; sometimes this was done in the 
field, but usually in the laboratory, large mats of the plants having been 
brought in and kept moist. As is well known, a male head collected at 
almost any season bears many antheridia in various stages of develop- 
ment. For the study of the younger antheridia, however, the verv small 
heads, which are most numerous in September, October and November, 
are most favorable; while older antheridia and mature antherozoids are 
most abundant (in this locality) in March, April and May. 
Of several modifications of Flemming’s chrom-osmic-acetic mixture 
that were used for fixation, the most favorable results were obtained 
with a solution prepared according to the following formula, which has 
been much employed in Strasburger’s laboratory; it is substantially 
the same as one published by Hof (1898), and identical with one given 
by Stomps (1910). 
1% chromic arid, 180 cc. 
2% osmic acid, 25 cc. 
Glacial acetic acid, 12 cc. 
Distilled water, 210 cc. 
A combination recommended by the Leeuwen-Reijnvaans (1907 b), 
of nine parts of Kaiser’s sublimate-acetic mixture with one part of for- 
malin, was also used. Material fixed in this was washed in fifty per cent 
alcohol, then in seventy per Cent aleohol containing iodine. Better differen- 
tial stains are obtained if the sections, after being mounted, are immersed 
for a few minutes in a solution of potassium permanganate. Even after 
this treatment, the staining reaetions are not as satisfactory as in Flemming 
material. The chromatin is more uniformly well fixed by this than by 
the chrom-osmic-acetic solution, but the fixation of the cytoplasm is not 
as good. As will appear later, I liave been unable to confirm most of the 
results obtained by the Leeuwen-Reijnvaans from material fixed in 
this same solution. 
