VAUIATIONS OF FUNGI. 59 



in some exotic Polypori. As regards the former case, Len- 

 thms lepldeus and Polyjjorus squamosus sometimes produce 

 little more than stems, and in the latter the stem becomes 

 so branched as to resemble a stag's-horn. Agaricus ostrea- 

 tus also, when grown in a vault, assumes sometimes a most 

 beautiful appearance, like that of a cauliflower, without any 

 definite pilei. Sometimes even in the open air the stem 

 swells above and forms a sort of club, without any pileus. 

 This is the case in Agaricus popinalis and the North Ameri- 

 can A. abortiviis. In some cases, again, the pileus, though de- 

 veloped, is never perfected, as in a curious form of Lentinus 

 tigrinns not uncommon in the United States, where the 

 whole forms a firm mass, suggesting, with its intricate abor- 

 tive gills, some new genus, rather than that to whicli it really 

 belongs. 



I may mention here that a strange transformation takes 

 place in a portion of the fruit of Agaricus racemosus. The 

 stem bears little pilei on its sides, as well as one which is 

 terminal. This latter has gills like a common Agaric, but 

 the lateral pilei are spurious, and have the structure of a 

 Stilbum. A somewhat analogous circumstance takes place 

 in some species of Ascophora, where the lower vesicles con- 

 tain very different sporidia from that which is terminal, 

 though in other respects the difference is not so striking as 

 in the Agaric just mentioned. Species of Nyctalis, when at- 

 tacked by Asterophoi-a, become nearly abortive, though there 

 is still some trace of gills. 



The spores of Agarics, though apparently perfect, are 

 sometimes deficient as to their internal structure, and there- 

 fore abortive ; and I have observed the sporidia in Sphceria 

 to become diseased from the conversion of their contents 

 into a dark solid mass. 



