BRYOPHYTES—MUSCI 
243 
like those shown in Figure 75 that it is better to use ice or Land’s cooler 
and get preparations from chromic material. 
Stages like that shown in Figure 75 are cut with comparative ease, 
for the calyptra is easily removed, and the capsule wall is not yet 
hard enough to occasion any difficulty. Safranin, gentian-violet, 
orange is a good stain. The cell walls stain so sharply that they are 
not obscured by a stain which will bring out the cell contents. 
Later stages, after the peristome 
has begun to differentiate, are likely to 
occasion difficulty in cutting. Bryum 
cuts as easily as any (Fig. 76). For 
the development of the peristome, fix 
in formalin alcohol and stain in safranin 
and anilin blue, or in safranin and 
light green. Safranin and Delafield’s 
haematoxylin is also an excellent stain 
for the older stages in the differentia¬ 
tion of the capsule. 
Beautiful mounts of the peristome 
are easily and quickly made. Take a 
capsule at the stage when the opercu¬ 
lum is just ready to fall off, or has just 
fallen off; with a sharp razor cut off 
the end of the capsule just below the 
line of the annulus; put it into absolute 
alcohol for 10 minutes, clear in clove oil, 
transfer to xylol, and mount in balsam. 
If several are placed on a slide, some 
one side up and some the other, with some complete and some teased 
a little, there will be good views of the entire peristome and also good 
views of teeth and cilia. 
The mature sporophytes of Sphagnum are exceptionally hard to 
cut. It will be worth while to prick the capsule with a needle when 
the material is collected. This will allow the fixing agent to penetrate 
readily, and will also facilitate the infiltration of paraffin or celloidin. 
The puncture causes only a slight damage, and need not reach the really 
valuable portion which is to furnish the median longitudinal sections. 
The younger stages in the sporophyte of Sphagnum like that shown 
in Figure 77, and also the antheridia, archegonia, and the peculiar 
development of the leaves cut easily in paraffin. 
Fig. 77.— Sphagnum: longitudinal sec¬ 
tion of sporophyte showing also the upper 
portion of the pseudopodium and the ca- 
iyptra—Delafield’s haematoxylin. X 24. 
