240 
METHODS IN PLANT HISTOLOGY 
of antheridia. Transverse sections show not only the antheridia, 
but also good views of the peculiar leaf of this genus. In all cases 
the stem should be cut off close up to the antheridia, for many of the 
moss stems, after they have begun to change color, cut like wire. 
Sections to show the development of the antheridium should be 
5 to 10 m in thickness. The safranin, gentian-violet, orange is a good 
Fig. 74. —Funaria hygrometrica: A, apex of young sporophyte showing endothecium and 
amphithecium—chromo-acetic acid and Delafield’s haematoxylin; 10 pt; X420; B, C, and D, 
transverse sections of a sporophyte of the same age as A, taken at different levels; X255.* 
combination (Fig. 73 A). For details of spermatogenesis, sections 
should not be thicker than 3 /jl. Iron-haematoxylin is a better 
stain for the chromatin and blepharoplasts. 
Although sections 20 to 50 /x in thickness can be cut to show 
topography, it is far better to study such stages in the fresh material. 
When a particularly fine view is secured in this way, a permanent 
preparation may be made by putting the piece into 10 per cent glycerin 
without any fixing or staining, and allowing the glycerin to concen¬ 
trate. Then mount in glycerin jelly. 
