240 Vniversitij of California Publications in Botany [Vol. 6 



The hyphae of the context are large in diameter (10 to \2^) and 

 so woven together that the tissue appears somewhat pseudo-parenchy- 

 matoiis. 



The structure of the hymenium is the same as in the case of Form 

 B described above. 



The surface of the stipe is not differentiated, except that the 

 hyphae at the surface have a somewhat smaller diameter (4 to 6(Lt) 

 and are darker in color that those of the context. As the center 

 of the stipe is approached, the hyphae increase in their diameter until 

 in the central portion hyphae occur which are 12 to 14|U in diameter. 



Ceriomyces comnmnis, Form D 



Plate 21, figure 5 



The plants referred to under Form D differ from those of Form 

 B in the following respects. The plants are smaller than is usual in 

 those referred to Form B, the pileus is 4 to 5 cm. in diameter, and 

 the stipe is about 6 cm. in length, somewhat enlarged below, with a 

 diameter at the top of 1.5 to 2.0 cm. and near the base of about 3.0 cm. 

 The base of the stipe is blunt and rounded and not attenuate into 

 a point as in Form B. The plants often occur two or three in a 

 cluster attached to one another at the base. The surface of the pileus 

 is tomentose and almost black in color. The tlesh of both pileus and 

 stipe is white, changing slowly to blue when wounded. The spores 

 in this form are 14 to 16 by 4 to 5/i., being slightly longer in proportion 

 to their diameter than those in Form B. A rather noticeable difference 

 between these plants and all other of our forms referred to C communis 

 is their freedom from attack by insect larvae. Insects are rarely 

 found in plants referred to this form, while in our other plants 

 referred to Ceriomyces comm/unis it is not at all unusual to find the 

 context of both stipe and pileus almost entirely eaten away. 



The description of Form D is based upon six plants collected near 

 Muir Woods, Marin County. Dried specimens of this form are de- 

 posited in the herbarium of the University of California under no. 238. 

 Plants which appeared to be identical with those referred to Form 

 D were observed in a field at Point Reyes, Marin County, and at 

 Brookdale in the Santa Cruz Mountains. 



Histology 

 Upon microscopic examination the surface of the pileus is seen 

 to be covered with hyphae arranged in tufts very much as described 



