SYSTEMATIC INDEX. 



thick, compact, firm, vanishing near the margin, 

 which is straight (never involute), spreading, 

 and without stride. Stem solid, at first hard, 

 then softer and spongy. Of the gills, a few 

 reach half-way to the stem ; the others are 

 divided, rigid, dilated in front, and extend into 

 a very broad, rounded end, whence the margin 

 of the pileus becomes obtuse and not inflexed. 



iv. Heterophyll^:. Pileus fleshy, firm, covered 

 with a thin adnate pellicle, margin thin, at 

 first turned in, then expanded and striate. 

 Gills many shorter mixed with the longer 

 ones, others forked. Stem solid, stout, spongy 

 within. 



v. Fkagiles. Pileus more or less fleshy, rigid, but 

 fragile, covered with a pellicle, always continu- 

 ous, viscid after rain, and somewhat separable, 

 margin membranaceous, at first closed in, but 

 not involute, when adult commonly sulcate and 



