74 Wisconsin Academy of Sciences, Arts, and Letters. 
f Presence of cuticle. 
| Color of flesh under cuticle. 
JPil<: us. ■'j Taste and odor. 
| Condition of margin, young and old (striate or even). 
[ Color of flesh when bruised. 
" Form. 
Thickness. 
Color, young and old. 
Gill 3. Surface, dusted or smooth. 
In ter venation. 
Equal, heterophyllous or branched. (Relative num¬ 
ber. ) 
Stem. 
-< 
Shape. 
Color, young and old. 
Substance. 
Changes in color. 
A classification according to color of the Russulas in the vicin¬ 
ity of Madison may be of service to the amateur collector. 
Red or blood colored: R. alutacea. R. emetica, R. roseipes, R. 
veternosa. 
Purple or livid: R. atropurpurea, R. integra, R. decolorans, 
R. amoena, R. ochrophylla, R. ochrophylla var. albipes. 
Brown or ferruginous: R. foetens, R. pectinata, R. ochracea «. 
Yellow: R. lactea, R. lutea. 
Green: R. viresccns, R. olivascens, R. furcata. 
Black: R. adusta, R. nigricans. 
White: R. delica. 
R. adusta (Pers) Fr. 
Pileus: convex, explanate or depressed, sometimes unequal; 
margin indexed and even; color, fuliginous, smooth, viscid 
when wet; 6-12 cm.; flesh, white. 
Gills: adnate or decurrent, not broad, narrow* tow r ard margin; 
white, changing to lead color, subcrow r ded, heterophyllous, 
forked occasionally. 
Stem: stout, cylindrical, fleshy, 3-4 cm. long, 1.5-2 cm. thick, 
smooth, white, soon becoming blackish. July and August. 
Spores: globose, slightly echinulate 6-9 u. 
