1916] Yates: Histology of Calif or nian Bolctaccae 247 



etc. Beneath the surface hiyer is the context, consistins: of nearly 

 hyaline hyphae 2 to 4/^ in diameter and very much interwoven. 



The structure of the hymcnivnii is exactly similar to the hymonium 

 of Form A described above. 



The reticulated upper portion of the stipe presents a very charac- 

 teristic appearance under the microscope. The reticulations appear 

 as ridges, 200 to 350/i, across at the base and rising 150 to 200/a above 

 the surface of the stipe. The depressions between the ridges, of course, 

 vary greatly in width, depending upon where the section was taken 

 (often 750 to 900;a) . The surface, both of the ridges and the depressions 

 between the ridges, is covered with a differentiated layer 45 to GOju in 

 thickness, formed of swollen, elub-.shaped tips of hyphae (J to 8/^i in 

 diameter, curved outward so that they stand in a position perpen- 

 dicular to the surface at their point of origin. This layer is yellowish 

 brown in color. Below the reticulations where the surface of the 

 stipe is smooth, the surface rind is formed of the same sort of club- 

 shaped hyphal tips as described above, but here they are not, of course, 

 raised so as to form ridges. 



The context of the stipe consists of interlaced hyaline hyphae 4 

 to 8fi in diameter (pi. 22. fig. 10). 



It seems probable that in these plants the hymenium is decurrent 

 on the stipe for some distance below the tubes, because basidia are 

 sometimes found among the club-shaped cells on the reticulations. 

 They seem to be typical basidia with four sterigmata. although spores 

 were never observed attached to them. 



Near the base, the stipe is covered with rind 200 to 250/x in thickness 

 formed of reddi.sh-brown hairs 4 to 8/x in diameter. These hairs are 

 very loosely interwined and appear to the naked eye as black scales. 



Ceriomyces auriflammeus (Berk. & Cui-t.) Mun-ill 



A single specimen of C. ai(ri/Unin)irus contributed by Dr. W. A. 

 I\Iurrill is described here for purposes of comparison. Murrill des- 

 cribes this species as follows : 



Pileus convex to expanded, 6-8 cm. broad, 1-2 cm. thick, surface dry, slightly 

 viscid after a rain, tomentose, bright yellow, sometimes partially covered with 

 a scarlet j)ulverulence; marj^in thin, entire, context white, unchanging, some- 

 what colored just beneath the pellicle, not bittcM-, tubes plane or convex, 

 adnate, radially elongate near the stipe, decurrent, greenish-yellow; mouths 

 angular, usually slightly scarlet when looked at sidewise, especially in dried 

 plants, rarely conspicuously scarlet over most of the hymenium; spores ])ale 



