254 University of California Publications in Botany [Vol. 6 



trees. One species, R. granulatus, is found in great abundance in the 

 Bay region during a long season, coming up after the first rains in 

 October and continuing to appear from time to time until about April. 

 According to Murrill's description, the genus Bostkovites is made 

 up of forms having an annual terrestrial hymenophore and differing 

 from other genera of Boletaceae with ochraceous or brown spores by 

 the presence of glandular dots on the stipe, as well as in the absence of 

 an annulus. The surface of the pileus is viscid, glabrous or hirtellous, 

 and has a yellow context which does not change color when wounded. 

 The yellow tubes are adnate and exude drops of a liquid which 

 blackens upon drying. The smooth, oblong-ellipsoidal spores are 

 yellowish brown. The stipe is solid, glandular-dotted, but not reticu- 

 late. In our Californian species the context of the stipe is yellowish 

 and unchanging in color. 



Rostkovites granulatus (L.) P. Karst 



This is probably our most common species of the Boletaceae. It is 

 usually found under Monterey pine {Pinus radiata), though the plants 

 sometimes occur under other species of pine. The plants may be col- 

 lected at almost any time after the first rains of the season until a 

 hot, dry spell comes, usually some time in April. 



Using Murrill's description as a basis, Rostkovites granulatus may 

 be described as including plants with a convex or nearly plane pileus, 

 the surface of which is very viscid or glutinous, with a surface cuticle 

 or "skin" which can be readily peeled away, exposing the white or 

 pale yellow context. The pileus varies in color from a light pinkish 

 or gray to a reddish brown color, or is often livid or sometimes spotted, 

 especially toward the center. The margin is sterile and usually in- 

 curved in young specimens. The context is thick and fleshy, white or 

 light yellow, and does not change to blue when wounded. The taste 

 is mild. The tubes are yellow, short (3mm. or less), adnate or sub- 

 decurrent, and plane in mass. They do not change color when 

 wounded. The large mouths are subcircular or angular, with black 

 granules in old specimens or drops of a whitish liquid in the younger 

 individuals. The spores are fusiform, varying in color from a light 

 yellowish brown to dark brown, 7.5 to 9.5 by 2.5 to 3.5/x. The stipe 

 is short, thick, subequal or enlarged below, white or pale yellow, 

 dotted with pinkish-brown droplets which become darker on drying. 



