BRYOPHYTES— MUSCI 



289 



sections to the slide. Remember that the dichromate of potassium in 

 this fixative is sensitive to light; so don't let the Hght strike it at the 

 wrong time. The stage shown in Figure 87 stains beautifully in Dela- 

 field's haematoxylin. It is not difficult to cut; because, at this stage, 

 the calyptra can be pulled off without injuring the top of the sporo- 

 phyte. From this stage, there is no difficulty until the peristome gets 



,»/ • 



B 



Fig. 87. — Funaria hygrometrica: A, longitudinal section of capsule; B, transverse section of 

 capsule of about the same age as A — Delafield's haematoxylin and erythrosin; 10 /i. 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 and the capsule begins to get brown (Fig. 88). As soon as the 

 brownish color begins to appear, it is hard to get good fixing in the 

 chromic series: better try formalin 10 c.c, acetic acid 5 c.c, and 70 per 

 cent alcohol 85 c.c. Remember that there should be a couple of days 

 in 85 per cent alcohol to insure perfect hardening. Safranin and Dela- 

 field's haematoxylin, or the triple stain, will be good for these later 

 stages. 



