FUNGI. 



67 



will show numerous brown or blackish specks scattered over 

 the patches. These are the spore fruits. 



For microscopical study, fresh material may be used, or, if necessary, 

 dried specimens. The latter, before mounting, should be soaked for a 

 short time in water, to which has been added a few drops of caustic-potash 



ar. 



FIG. 39. A, spore-bearing filaments of the dandelion mildew (Podosphssra), 

 x 150. B, a germinating spore, x 150. C-F, development of the spore fruit, 

 x 300. ar. archicarp. G, a ripe spore fruit, x 150. H, the spore sac removed 

 from the spore fruit, x 150. /, spore-bearing filament attacked by another 

 fungus (Cicinnobulus) , causing the enlargement of the basal cell, x 150. 

 J, a more advanced stage, x 300. K, spores, x 300. 



solution. This will remove the brittleness, and swell up the dried fila- 

 ments to their original proportions. A portion of the plant should be 

 carefully scraped off the leaf on which it is growing, thoroughly washed in 

 pure water, and transferred to a drop of water or very dilute glycerine, 

 in which it should be carefully spread out with needles. If air bubbles 

 interfere with the examination, they may be driven off with alcohol, and 

 then the cover glass put on. If the specimen is mounted in glycerine, it 

 will keep indefinitely, if care is taken to seal it up. The plant consists of 



