68 NEW YORK STATE MUSEUM 



I Lamellae often forked, narrowed toward each end Furcatae 



I Lamellae often forked, narrowed toward the stem Rigidae 



2 Lamellae unequal, viscid pellicle adnate Heterophyllae 



2 Lamellae mostly equal, viscid pellicle separable Fragiles 



Compactae Fr. 



Pileus fleshy, compact, firm, without a separable pellicle and with- 

 out striations on the margin; lamellae unequal; stem firm, solid, 

 rarely cavernous when old. 



In all our species the spores are white. In nearly all, wounds of 

 the lamellae or flesh change color. Five of the species are so closely 

 related that in the dried state it is scarcely possible to separate them 

 from each other satisfactorily. Their diiTerential characters are chiefly 

 such as can be ascertained only in the living plant. All are mild or 

 tardily acrid in taste. The compact flesh, even margin of the pileus 

 and unequal lamellae are the prominent characters of this subgenus. 



KEY TO THE SPECIES 



Pileus changing color with age or in drying i 



Pileus persistently white or whitish 7 



I Pileus becoming smok}^ brown, grayish brown or blackish 2 



I Pileus becoming pale tawny or rusty ochraceous 6 



2 Pileus viscid when moist 3 



2 Pileus dry 4 



3 Lamellae and flesh slowly becoming reddish where wounded nigricans 



3 Lamellae and flesh not becoming reddish where wounded subsordida 



4 Flesh slowly becoming reddish where wounded densifolia 



4 Flesh not becoming reddish where wounded 5 



'5 Flesh becoming black or blackish where wounded sordida 



5 Flesh not changing color where wounded adusta 



6 Pileus viscid when moist, odorous magniiica 



6 Pileus dry, inodorous when fresh compacta 



7 Lamellae persistently white delica 



7 Lamellae becoming subferruginous in drying brevipes 



Russula nigricans (Bull.) Fr. 

 BLACKISH RUSSULA 



Pileus thick, firm, at first convex and umbilicate with the margin 

 incurved, becoming expanded and centrally depressed, at first white 

 or white clouded with smoky brown, slightly viscid, becoming black- 

 ish or blackish brown, flesh white, first slowly changing to a reddish 

 hue when cut or broken then becoming blackish, taste mild ; lamellae 

 broad, subdistant, slightly rounded behind, adnexed, white becoming 



