The Scottish N'aturalist. 251 



J. Berkeley, whose opinion will be found recorded in the ' Gar- 

 deners' Chronicle' for December 15, 1877, p. 723. I sent speci- 

 mens also to Professor Fries, who fully confirmed the conclusion 

 that they represent Ptychogaster in true polyporoid form. He 

 further informed me that he had gathered specimens of Polyporus 

 borealis, which confirmed his views ; and he pronounced the 

 unqualified judgment — " Est itaque anomalum hoc genus de- 

 lendum." 



So far as regards the extinction henceforth of the genus Pty- 

 chogaster, the results of these discoveries are satisfactory. But 

 in its origin and development this curious phase of fungoid 

 growth remains an unsolved problem. 



Fries, in his letter, speaks of Ptychogaster " in transitu ad Poly- 

 poros." His theory, therefore, would regard Ptychogaster as an 

 arrest, so to speak, in the development of a Polyporus. 



Mr Berkeley says : " It does not seem, however, that it is a 

 degeneration of the Polyporus, but rather the work of a parasite, 

 which modifies the matrix in the same way that Nyctalis and 

 Boletus are affected by their peculiar parasites. The parasite, 

 however, cannot be referred to the Myxogastres, nor do the 

 threads seem to belong to the parasite, but to be derived from 

 the matrix, just as those are which occur in Ustilago oUvacea^ 



Mr Berkeley observes of the specimens which he received ; 

 " Before making a section, part of the specimen was seen to be 

 in the usual condition of the Ptychogaster, consisting of erect 

 irregular threads and abundant ochraceous spores, the other half 

 exhibiting something like sinuous pores, but so soft and tender 

 that it was difficult to say what their real nature might be. How- 

 ever, on making a section, not only was a white, firm base dis- 

 covered, but pores in the normal condition of those of the Poly- 

 porus in question {Polyporus destructor). ^^ 



Among the specimens which I gathered there were some which, 

 on the upper side, assumed the condition of Ptychogaster, while 

 the under portion consisted of the normal pores of Polyporus, 

 perfect in form, and pure white, even at the orifices. Some of 

 these, however, after being gathered, soon passed into the condi- 

 tion described by Mr Berkeley when the specimens reached him. 

 The pores in others remain more or less perfect at the orifices, 

 ihough covered with the ochraceous spores. So perfect indeed 

 were some of the specimens, — polyporoid on the under surface, 

 ptychogastric on the upper, — that, at first sight, it might almost 

 seem that a perfect Polyporus was passing into Ptychogaster. 



