WHITE-SPORED AGARICS. 125 



Lactarius indigo (Schw.) Fr. The indigo blue lactarius is a very 

 striking and easily recognized plant because of the rich indigo blue 

 color so predominant in the entire plant. It is not very abundant, 

 but is widely distributed in North America. The plant is 5-7 cm. 

 high, the cap 5-12 cm. broad, and the stem is 1-2 cm. in thickness. 

 The plants occur during late summer and in the autumn. 



The pileus when young is umbilicate, the margin involute, and in 

 age the margin becomes elevated and then the pileus is more or less 

 funnel-shaped. The indigo blue color is deeply seated, and the sur- 

 face of the pileus has a silvery gray appearance through which the 

 indigo blue color is seen. The surface is marked by concentric zones 

 of a darker shade. In age the color is apt to be less uniformly dis- 

 tributed, it is paler, and the zones are fainter. The gills are crowded, 

 and when bruised, or in age, the indigo blue color changes somewhat 

 to greenish. The milk is dark blue. 



RUSSULA Pers. 



The species of Russula are very characteristic, and the genus is 

 easily recognized in most cases after a little experience. In the very 

 brittle texture of the plants the genus resembles Lactarius, and many 

 of them are more brittle than the species of this genus. A section 

 of the pileus shows under the microscope a similar vesicular condi- 

 tion, that is the grouping of large rounded cells together, with threads 

 between. But the species of Russula are at once separated from 

 those of Lactarius by the absence of a juice which exudes in drops 

 from bruised parts of Lactarius. While some of the species are white 

 and others have dull or sombre colors, many of the species of Russula 

 have bright, or even brilliant colors, as red, purple, violet, pink, blue, 

 yellow, green. In determining many of the species, however, it is 

 necessary to know the taste, whether mild, bitter, acrid, etc., and in 

 this respect the genus again resembles Lactarius. The color of the 

 gills as well as the color of the spores in mass should also be deter- 

 mined. The genus is quite a large one, and the American species 

 are not well known, the genus being a difficult one. In Jour. Myco- 

 log., 5: 58-64, 1889, the characters of the tribes of Russula with 

 descriptions of 25 species are quoted from Stevenson, with notes on 

 their distribution in N. A. by MacAdam. 



Russula alutacea Fr. Edible. This handsome Russula differs from 

 the others described here in the color of the gills and spores. The 

 plant is common and occurs in mixed woods during the summer and 

 early autumn. It is 5-10 cm. high, the cap 5-12 cm. broad, and the 

 stem 1.5-2.5 cm. in thickness. 



