Myxomycetes and Schizophytes 



159 



haematoxylin and very lightly in erythrosin, the latter stain being 

 used merely to outline the sheath. When ready for mounting, 

 crush a small nodule under a cover-glass. The paraffin method is 

 easily applied, since the gelatinous matrix keeps the filaments in 

 place. Any form of similar habit may be prepared in the same way. 



Gloeotrichia.- 

 Gloeotrichia (Fig. 30), 

 in its later stages, is a 

 free-float ing form. In 

 earlier stages it is at- 

 tached to various sub- 

 mersed aquatic plants. 

 The nodules, when 

 young, are firm like 

 Nostoc, but as they 

 grow older and larger &, ' 



they become hollow 

 and soft. The older 

 forms become so much 

 dissociated that they 

 lose their character- 

 istic form and merely 

 make the fixing fluid 

 look turbid. Allow a 

 drop of such material 

 to spread out and dry 

 upon a slide which has 

 been slightly smeared with albumen fixative. Leave the slide in 95 

 per cent alcohol 2 or 3 minutes to coagulate the albumen fixative, 

 and then stain in safranin. If the background appears untidy, stain 

 for 24 hours, or longer; you can then extract the stain from the back- 

 ground, and still leave the long spore and some of the other features 

 of the filament well stained. A touch of cyanin will bring out 

 the sheath. Cyanin and erythrosin is a good combination if the 

 material is clean. The firmer nodules may be treated like Nostoc or 

 Rivularia. 



FIG. 30. Gloeotrichia: photomicrograph from a prepa- 

 ration stained in cyanin and erythrosin; negative by 

 Dr. W. J. G. Land. 



