Polyporacese 



BOLE'TUS Dill. 

 Gr. a clod. 



Boletus. ^Ba name of a fungus considered a great delicacy 



among the Romans, derived from bolos, a clod, 

 probably to denote the round figure of the plant. 

 Hymenium wholly composed of small tubes, 

 connected together in a stratum, the surface of 

 which is dotted with their poriform mouths, and 

 which is distinct from the hymenophore on ac- 



count of the latter not descending into a trama. Tubes packed close 

 together, easily separating from the hymenophore and from one another. 

 Pores or mouths of the tubes round or angular (in the subgenus Gyrodon 

 sinuous or gyroso-plicate ) . Spores normally fusiform, rarely oval or 

 somewhat round. Growing on the ground, fleshy, putrescent, with cen- 

 tral stems. Mostly edible, and of importance as articles of food; a few 

 poisonous. Fries. 



No American species in Gyrodon. It is therefore omitted in synopsis 

 of tribes. C. M. 



This genus abounds in species and is related to Boletinus on one hand 

 and to Polyporus on the other. From the latter it is distinguished by 

 the absence of a trama and from both by the tubes being easily separa- 

 ble from the hymenophore and from each other. Some of the species 

 are very variable, others are so closely allied that they appear to almost 

 run together. 



The species are generally terrestrial, but B. hemichrysus is habitually 

 wood-growing, and others are occasionally so. 



The spores vary so much in color in such closely related species that 

 this character is scarcely available for general classification, but it is val- 

 uable as a specific character and should always be noted. 



SYNOPSIS OF THE TRIBES. 



Pileus and stem yellow-pulverulent, stem not reticulated 



with veins .................... (p. 421.) Pulverulent! 



Pileus and stem not yellow-pulverulent, or if so then 



the stem reticulated with veins ..................... I 



I. Tubes yellowish with reddish, or reddish-brown 



mouths ........................... (p. 453.) Luridi 



404 



