86 NEW YORK STATE MUSEUM 



Fragiles Fr. 



Pileus fragile, covered with a thin separable or subseparable pel- 

 licle, viscid when moist, thin on the margin which is commonly 

 striate or tuberculose striate in the mature plant ; lamellae equal or 

 nearly so, broader anteriorly; stem soft, spongy or hollow. 



The fragile character of the pileus, the viscid separable pellicle, 

 the thin and ultimately striate or tuberculose striate margin and 

 the usually equal simple lamellae are the prominent distinguishing 

 features of this subgenus. Its species outnumber those of any other 

 subgenus of Russula. They may be divided into three groups de- 

 pending on the color of the spores, which color is frequently indi- 

 cated by the color of the mature lamellae. There are some excep- 

 tional or anomalous cases in which all the characters attributed to 

 this tribe are not shown by species included in it. In some species 

 the pileus is not viscid or the margin is not striate or the pellicle 

 may be separable on the margin but not on the disk. The tubercu- 

 lose character of the marginal striations is apparently due to the 

 venose interspaces. 



KEY TO THE SPECIES 



Spores white or whitish i 



Spores pale a'cIIow or citrine lo 



Spores ochraceons 20 



1 Pileus red or reddish 2 



I Pileus ochraceous or yellowish brown 7 



I Pileus white or whitish 8 



2 Taste acrid 3 



2 Taste mild 6 



3 Pileus even 4 



3 Pileus rugulose rugulosa 



4 Pileus darker colored in the center '. fallax 



4 Pileus typically uniformly colored 5 



5 Lamellae rounded l)ehind. subf ree, subdistant emetica 



5 Lamellae adnexed, close f ragilis 



6 Stem white or reddish uncialis 



6 Stem red or deep red purpurina 



7 Stem white pectinatoides 



7 Stem pale ochraceous simillima 



8 Taste acrid anomala 



8 Taste mild 9 



9 Pileus dry albella 



9 Pileus viscid albida 



10 Pileus red or some shade of red ♦ 11 



10 Pilous some other color 17 



I I Taste acrid veternosa 



II Taste mild or slightly and tardily acrid 12 



