1916] Yates: Histology of Calif ornian Boletaceae 251 



The following is a brief description of SuiUelhis Eastwoodeae Form 

 B. Plants solitary on llic ground: pilcus thick, compact, hemispheric, 

 15-22 cm. broad, surface smooth, glabrous, not viscid, reddish brown, 

 margin entire; slightly projecting context firm, white or liglit yellow 

 changing quickly to blue when wounded and then slowly (or not at all) 

 changing to yellow and finally to a dirty white. Tubes adnate, sep- 

 arating with age, about 1.5 to 2.0 cm. long, concave to plane in mass, 

 yellow, mouths small, anguhir, red. Spores oblong-ellipsoidal, smooth, 

 brownish, 8 to 9 l)y 4 to 5/^. Stipe bulbous at the l)ase, reticulated 

 above the swelling, the stipe above the bull) is red, the swollen base is 

 brown. Stipe solid, context of stipe above bulbous base concolorous 

 with the context of the pileus and undergoing the same color changes. 

 The context of the bulbous portion of the stipe is brown, unchanging. 

 The stipe is 10 to 14 em. long, 6 to 7 cm. thick above the bulbous ])or- 

 tion, which is 8 to 12 cm. thick. 



The differences between these plants and Suillellus Eastwoodeae 

 as described by jMurrill and illustrated by Form A are as follows : In 

 the first place the plants are very much larger in every way than are 

 those of S. Eastwoodeae as described by Murrill. The color of the sur- 

 face of the pileus is reddish in these plants, while in S. Eastwoodeae 

 it is described as light brown by ]Murrill. Moreover, the color-changes 

 differ somewhat. The tubes are considerably longer, being nearly 

 twice as long in .some individuals as are those of S. Eastwoodeae. The 

 spores also differ slightly in size. When we come to consider the stipe, 

 however, we find the greatest and most remarkable differences. In- 

 stead of being enlarged at the center as is described for S. Eastwoodeae 

 and illustrated in Form A, it is decidedly bulbous at the base. The 

 surface of the stipe of 8. Eastwoodeae is described by IMurrill as even 

 and glabrous, while in these plants the stipe above the bulbous portion 

 is decidedly reticulate. 



Histology 



Under the microscope the surface of the pileus is seen to be covered 

 with long hairs, 1 to 'lix in diameter, and 80 to lOO/x in length. These 

 hairs are unbranched and have few septa. Below these hairs is a rind 

 40 to 50/A in thickness made up of brow^n, densely interwoven hyphae, 

 1 to 2ju in iliameter and septate. The context is formed by interwoven 

 hyaline hyphae 4 to 8/i in diameter (pi. 22, fig. 15). 



The hymenium is made up of paraphyses and basidia and in this 

 form the basidia do not stand out above the paraphyses. There were 



