.371 



KoTE ON Fungi Parasitic on Diatoms. 

 By J. G. Gkexfell, B.A., F.R.M.S. 



{TaJcen as read February 1 0th, IS04) 



In the Botanical Gardens in the Regent's Park there are 

 now to be found specimens of Chytridiaceous fungi parasitic on 

 diatoms. They occur on Stauroncis p^Kjenicenteroji, and on a very 

 small Navicula, probably N. sphct^rophora. 



The parasite of Stauroneis is an apparently new species of 

 the genus Rhizophidium. The branching mycelium embracing 

 the chromatophores of the diatom is very well seen. The 

 external zoosporangium is pear-shaped. The parasite of the 

 Navicula is probably distinct. jSTo mycelium has yet been seen. 

 The general appearance of both is very similar to the Septocar- 

 pus figured in the Quekett Club Joarnal for July, 1889, Plate 

 II., appended to Mr. Karop's translation of a paper by Zopf. 

 In Septocarpus, however, the lower portion of the sporangium 

 is shut off by a septum, and contains no swarm-spores. There 

 is no trace of this here. Several chytridiaceous fungi have been 

 found on diatoms in Germany, but none have been recorded in 

 England. 



