WHITE-SPORED AGARICS. 



117 



Figure ii8 is from plants (No. 3910, C. U. herbarium) collected 

 in the woods at Blowing Rock, during September, 1899. Just before 

 the exposure was made to get the photograph several of the plants 

 were wounded with a pin to cause the drops of milk to exude, as is 

 well shown in the illustration. 



The dark color of the lamellae in L. corrugis is due to the number 

 of brown cystidia or setae, in the hymenium, which project above the 

 surface of the gills, and they are especially abundant on the edge of 

 the gills. These setae are longfusoid, 80-120 x 10-12 //. The vari- 

 ations in the color of the gills, in some plants the gills being much 

 darker than in others, is due to the variations either in the number 

 of these setae or to the variation in their color. Where the cystidia 

 are fewer in number or are lighter in color the lamellae are lighter 

 colored. Typical forms of Lactarius volemus have similar set^, but 

 they are very pale in color and not so abundant over the surface of 

 the gills. In the darker forms of L. volemus the setae are more abun- 

 dant and darker in color, approaching those found in L. corrugis. 

 These facts, supported by the variation in the color of the pileus in 

 the two species 

 and the varia- 

 tions in the ru- 

 gosities of the 

 pileus, seem to 

 indicate that 

 the two species 

 arevery closely 

 related. 



Lactarius lig 

 nyotus Fr. 

 This is known 

 as the sooty 

 lactarius and 

 occurs in woods 

 along with the 

 smoky lactari- 

 us. It is dis- 

 tinguished from 

 the latter by 

 the dark brown 

 color of the pi- 

 leus and by the presence usually of rugose wrinkles over the center 

 of the cap. In size it agrees with the smoky lactarius. 



Figure 119. Lactarius lignyotus. Cap and stem sooty, cap wrinkle 

 gills white, then tinged with ochre (natural size, sometimes largei 

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