2i6 British Funoi. 



<i> 



Kemembering the great difficulty experienced in 

 distinguishing so-called species of Saprolegnia even 

 in the living state from purely morphological 

 characters, or even distinguishing between the genera 

 Saprolegnia and Peronospora when sexual portions 

 alone are present^ from the same characters it can be 

 readily understood that the difficulties must be greatly 

 increased when dealing with fragmentary fossil re- 

 mains. It is doubtful whether the fungus under 

 consideration was not better placed by Smith in the 

 Peronosporese than by Williamson in the Saprolegnise. 

 Members of the latter group do not as a rule produce 

 their oosronia in tissues, whereas this is usual in the 

 Peronosporefe. It is not usual for septa to be entirely 

 absent^ especially at the base of the oogonia, as be- 

 lieved to be the case by Professor Williamson in his 

 specimens^ which after all may be distinct from 

 Smithes fungus. 



Several other species of fungi apparently belonging 

 to the Phy corny cetes have been described as occurring 

 in the tissues of fossil plants. 



Mr. Carruthers has described the mycelium of a 

 fuugfus resembliuo' Peronosiwra found in the tissues 

 of a fossil fern, Osmundites Doiul-eri, Carr., from the 

 lower Eocene of Heme Bay. Other forms are de- 

 scribed by Cash in a paper entitled, *' On the Fossil 

 Fungi from the lower Coal-measures of Halifax,^' read 

 before the Yorkshire Geological and Polytechnic 

 Society in 1879. 



