260 FUNGUS-FLORA. 



ANALYSIS OF THE SPECIES OF BOLETUS. 

 A. Pores yellow at the openings. 



Under this division are included those species having the 

 openings of the pores yellow, orange, greenish, or cinnamon- 

 brown when mature. 



* Ring present on stem. 



** Pileus dry, tomentose or silky. 



*** Pileus viscid, at least when moist ; ring absent. 



**** Stem reticulated. 



B. Pores red at the openings, tubes more or less olivaceous. 



The red colour of the openings of the pores varies from 

 crimson, through purple, to brownish red. 



C. Tubes red throughout. 



The entire length of the tubes as well as the openings of 

 the pores red. 



D. Tubes pale, dingy pink throughout. 



The entire length of the tubes, as well as the openings of 

 the pores, dingy pink or pale flesh-colour. 



E. Tubes and openings of pores white or grey. 



In the present section both tubes and openings of pores 

 are white at first, then often grey, in some species becoming 

 brownish; but there is not at any age the least trace of 

 yellow or red. 



Subgen. Gyrodon. 

 Tubes exceedingly short, openings sinuous. 



The above characters apply to the mature fungus ; in 

 many species of Boletus the tubes in the young state answer 

 more or less to the above diagnosis, but the tubes elongate 

 and the openings expand during development. 



