250 University of California Publications in Botany [Vol. 6 



Histology 



Upon examination under the microscope the surface of the pileus 

 is seen to be covered with a rind 20 to 25/x in thickness, formed of 

 intertwined broM'nish hairs 4 to 6/x in diameter. Beneath the hairs 

 there is a definite layer 60 to lO/x thick formed of hyphae which are 

 very firmly packed together. This inner layer differs from the outer 

 simply in the closer packing of the hyphae. Sometimes the surface 

 of the pileus seems to be covered with a jelly-like substance without 

 any hairs. This jelly is very likely formed by the breaking down of 

 the walls of the hairs soon after the plants reach maturity. The con- 

 text of the pileus is formed of intertwined hyaline hyphae ranging 

 in diameter from 4 to Sjx up to even 10 to 12/j,. 



The hymenium consists of basidia and paraphyses only, no cystidia 

 having been observed. The basidia when mature rise above the para- 

 physes a distance of about 2/a. 



The rind of the stipe varies considerably in its thickness. In some 

 places the rind is quite thick (40 to SOyii) but in other places it may 

 be only 10 to 20/x in thickness. In either case the rind is formed of 

 the same sort of hyphae. The hyphae forming the rind are 2 to 4/x 

 in diameter, brown in color and very closely woven together. Be- 

 neath the rind is the context, made up of hyaline hyphae 4 to G/x in 

 diameter near the surface and increasing in diameter up to 16 to 18ju, 

 as the center of the stipe is approached. The hyphae of the context 

 usually lie in a position generally parallel to the long axis of the stipe. 



Suillellus Eastwoodeae, Form B 



Plate 21, figure 6 



The plants described below were determined by W. A. IMurrill from 

 dried material, as a form of Suillellus Eastwoodeae, but they differ 

 from that species in so many respects that they might well be con- 

 sidered to belong to a distinct species. The description given below is 

 based upon five specimens collected near Muir Woods, Marin County, 

 on October 21, just after the first heavy rain of the season. The plants 

 were growing in moist ground under the shade of a mixed forest of red- 

 wood (Sequoia sempervirens) , Douglas fir {Pseudotsuga taxifolia), 

 madrone { Arbutus Menziesii), live oak [Quercus agrifolia), and tan 

 oak (Pasania densi flora). Dried specimens of this form are filed in 

 the herbarium of the University of California under No. 239. 



