290 THE AGARICACEAE OF MICHIGAN 



may break up into easily removed shreds, so that it may appear to 

 be lacking in rainy weather. The SPORES are elliptical or oval, 

 non-angular except obscurely so in a few species, e. g. P. acericola, 

 P. hoiveana and P. aegerita; in P. aggericola they are often some- 

 what pear-shaped. The color when caught on white paper varies 

 considerably, and has been used to subdivide the sections. 

 CYSTIDIA are present only in two sections, as far as is known, 

 viz. in the Humigeni and Hygrophani. This fact may serve as a 

 basis for raising these sections to generic rank, as has been done 

 by Earle and others. 



The genus Pholiota furnishes some excellent species for the table. 

 P. praecox and its near relatives are among the early edible 

 mushrooms, and as they occur on lawns and grassy places are 

 within easy reach. A number of the large, caespitose forms, like 

 P. squarrosa, P. squan-osoides and P. adiposa are among those eaten, 

 and in Europe P. mutabilis is highly prized as an ingredient of 

 soups, and is often artificially cultivated on the wood on which 

 it is found. On the other hand, wood-inhabiting Pholiotas as well 

 as others, are apt to have a strong odor or taste, derived from the 

 wood, and this does not always disappear on cooking. As far as 

 known, no virulent poisons are present in any of this genus. 



The genus is rather large, but many species are found rather in- 

 frequently. The following key includes most of the species reported 

 for the north-eastern United States, and no doubt some which are 

 not yet described will be discovered from time to time. Fries 

 divided the genus into three sections; to these I will add the sub- 

 division Hygrophani, as they seem to stand out sufficiently clear 

 from the rest of the species. The four sections follow : 



I. Humigeni 



II. Truncigeni 



III. Hygrophani 



IV. Muscigeni 



Key to the Species 



(A) Pileus viscid when moist. [See also (AA) and (AAA).] 



(a) Pileus scaly; often very caespitose; on wood, sometimes on debris, 

 (b) Pileus bright yellow. 



(c) Gills broad, adnate then emarginate, at first yellow; pileus very 



viscid, ochre-yellow, 

 (cc) Gills narrow. 297. P. adiposa Fr. 

 (d) Gills yellow at first; pileus sulphur-yellow, covered with 

 tawny or reddish-brown scales; stem peronate. 299. P. 

 lucifera (Lasch.) Bres. 

 (dd) Gills whitish at first; pileus lemon-yellow. P. limonella Pk. 

 (bb) Pileus not at all or tinged slightly with yellow. 



