Bryophytes Musci 



219 



material cuts more easily, chromo-acetic acid followed by Dela- 

 field's haematoxylin gives so much sharper differentiation in stages 

 like those shown in Fig. 70 that it is better to use ice or Land's cooler 

 and make an effort to get preparations from chromic material. 



Stages like that shown in Fig. 70 are cut with comparative ease, 

 for the calyptra is easily removed, and the capsule wall is not yet 



B 



FIG. 70. Funaria hygrometrica: A, longitudinal section of capsule; B, transverse 

 section of capsule of about the same age as A Delafleld's haematoxylin and erythrosin; 

 10 M. The columella, archesporium, outer spore case, two layers of chlorophyll-bearing 

 cells, and the beginning of the air spaces can be distinguished at this stage. X420. 



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. 71). For the development of the peristome, fix in formalin 

 alcohol and stain in safranin and anilin blue, or in safranin and light 



