presents the form of the normal species, it is often so modified that 

 it is Difficult to trace the connection. It is generally recognized tha 

 Ptychogaster is a modification or a conidial form' of a Polyporus 

 but I have seen no explanation or theory to account for it. 



PTYCHOGASTER ALBUS (Fig. 2 6 5 ).-All species of Ptycho- 

 gaster are rare, but this is the most frequent and best known f have 

 collected it several times in Sweden, but it is reported rare in 'England 

 and France. 1 do not know it from the United States, where it has 

 been recorded by Peck. 



When young it is white and soft and has somewhat the appearance 

 of a Spumaria. Its form is usually nearly globose, and the surface 

 is pubescent with the projecting fibrils. When broken open it is 

 found to consist of soft fibrils, powdery with abundant, conidial spores. 

 These spores are globose, hyaline, smooth, very small, about y. mic. 

 in diameter, I judge. When old the plant becomes brownish. 



Fig. 266. 

 Ptychogaster hepaticus x 6. 



I found the plant several times in Sweden, but never saw any connection 

 between it and Polyporus borealis, and had I not known it to be a conidial 

 form I should never have suspected any connection. Why Fries first reached 

 this conclusion I do not know. 30 I have never seen them growing together; 



36 One author, Ludwig, claims that Ptychogaster albus is a form of "its own proper 

 species," which he calls Polyporus Ptychogaster, as found in Saccardo. I think no one else 

 believes it. The statement by Berkeley that Fries considered it a monstrosity of Polyporus 

 destructor is an error, for Fries referred it to Polyporus borealis. 



31 



