218 



Groups of North American Boleti 

 Tubes separated from each other ; stem lateral ; plants found on decaying stumps, 

 trunks or roots. ^ 



Tubes attached to each other ; stem central, rarely eccentric ; plants terrestrial, except 

 in very rare instances. 

 Tubes arranged in radiating rows. B 



Tubes usually small, not arranged in radiating rows. 

 Pileus conspicuously floccose. 



Spores blackish brown. C 



Spores ferruginous. ( Boletus Ananas. ) D 



Pileus glabrous or subtomentose. 



Stem annulate. E 



Stem exannulate. 



Stem and tubes glandular-dotted with a gummy secretion that 



hardens and turns black soon after exudation. F 



Stem shaggy and lacerate, with deep reticulated furrows ; spores 



olive-brown. G 



Stem hollow at maturity ; spores pale yellow, elliptical. H 



Stem and pileus covered with a conspicuous sulphur-yellow 



powder. * 



Not as above. 



Spores flesh-colored; tubes adnate, whitish, tinted by the 

 spores at maturity. J 



Spores not flesh-colored, usually yellowish brown. 



Tubes with red or reddish brown mouths, yellowish 

 within. K 



Tubes not as above. 



Tubes free, white, not stuffed when young ; stem 



not reticulated, often scabrous. L 



Tubes adnate, white ar yellow, not stuffed when 



young. 



Stem reticulated. M 



Stem not reticulated. N 



Not as above. 



New York Botanical Garden. 



