FUNGI 



257 



found on insects, fishes, dead fish eggs, and on algae. The zoospores 

 escape in a mass, whicli, for a short time, is held together by a trans- 

 parent pellicle; in Saprolegnia the zoospores swarm separately. In 

 Saprolegnia, the new sporangia grow up through the empty ones; in 

 Achlya, the later sporangia arise on lateral branches below the earlier 

 ones. Didyuchus and Olpidhan often appear when one is trying to get 





Fig. 66. — Albuyo Candida: A, small portion of a section of a blister showing coenocytic myceli- 

 um, conidiophores, and multinucleate conidia. B, a young oogonium with large coenocentrum and 

 many nuclei. C, later stage, after differentiation into a central ooplasm, surrounded by the multi- 

 nucleate periplasm; all of the nuclei of the ooplasm, except one, have disorganized. Fixed in the 

 special chromo-acetic acid solution and stained in iron-alum haematoxylin and orange. X780. 



Saprolegnia or Achlya. The fixing and staining described for Sapro- 

 legnia will give good results with the other genera. 



Albugo. — This fungus is quite common on Cruciferae, where the 

 white "blisters" or "white rust," Albugo Candida, form quite con- 

 spicuous patches. Affected portions of leaves and stems should be 

 fixed in chromo-acetic acid and cut in paraffin. Sections 5 ^ or less in 

 thickness will be found most satisfactory. Stain in iron-alum and 

 counter-stain lightly with orange (Fig. 6G). 



