UNIVERSITY OF CALIFORNIA PUBLICATIONS 



IN 



BOTANY 



Vol. 6, No. 10, pp. 221-274, plates 21-25 Issued February 25, 1916 



THE COMPARATIVE HISTOLOGY OF CERTAIN 

 CALIFORNIAN BOLETACEAE 



BY 

 HAERY S. YATES 



The Boletaceae constitute a relatively small family of the group ^v^ , 



of fungi known as the Hymenomycetales ( Hymenomyeetineae, Hymen- '^r^ v 

 omyeetes.) The Hymenomycetales are fungi whose spores are ab- ^^o^ 



jointed from basidia which are all at the same level and form a layer 

 known as the hymenium. Until quite recently the Boleti have been 

 considered as a subdivision under the Polyporaceae or "pore fungi." 

 In this more comprehensive sense the Polyporaceae embrace all fungi 

 in which the spore-bearing surface lines the interior of tubes, together 

 with certain related forms included imder the genera Lenzites, Irpex, 

 and Mendius. IMore recently Dr. W. A. Murrill of the New York 

 Botanical Garden has adopted a division of the Polyporaceae, or 

 "pore fungi." into two families, the Polyporaceae and Boletaceae. 

 The Polyporaceae are commonly leathery, corky, or woody in texture 

 and the tubes, as a rule, do not separate readily from the pileus. 

 ^Moreover the plants usually grow upon wood (epixylous). The Bole- 

 taceae are fleshy in texture, the tubes, in nearly all cases, separate 

 very readily from the rest of the pileus and furthermore only a few 

 species grow upon wood. 



The Boletaceae are a small group of fleshy fungi with the hymenium 

 lining the interior of tubes which are placed close together on the 

 underside of the pileus or cap. The plants have both a pileus and a 

 stipe or stalk. Frequently a veil is present, at lea.st during the earlier 

 stages, but sometimes the Boleti are practically gymnocarpous (com- 

 pare Zeller, 1914). Nearly all the Boletaceae are terrestrial; only 

 three or four species occur upon wood. With few exceptions the 

 Boleti are seemingly saprophytic, mostly on decaying leaves or twigs. 

 The plants grow in woods or along their borders. In California the 

 writer has never found them in open fields. Some of the species are 



