326 Murrill: Polyporaceae of North America 



some of thein vary to centrally stipitate forms and a few species are 

 regularly mesopous. All grow upon dead wood and agree closely 

 in habit and host plants. One American species is common also 

 in Europe, the others are limited to either temperate or to tropical 

 regions of America. Many of them are very imperfectly known. 



Synopsis of the North American species 



1. Tubes unequally hexagonal, the radial walls longer. 2. 

 Tubes equally hexagonal 15- 



2. Pileus white or nearly so. 3- 

 Pileus purple or brown. 12. 



3. Surface of pileus glabrous or minutely hairy or fibrillose, not distinctly hispid or 



tomentose. 4- 



Surface of pileus distinctly hispid or tomentose. 9. 



4. Pileus reniform at maturity, stipe usually much reduced ; species not tropical. 5. 

 Pileus flabelliform, stipe usually very distinct, equalling the pileus at times in 



length ; species tropical. 6. 



5. Tubes large, surface of pileus decorated with imbricated reddish-brown fibrils, 



which disappear with age. I. H. alveolaris. 



Tubes much smaller, the mouths rarely over 1 mm. long and 0.5 mm. broad, 



surface of pileus glabrous. 2. H. micropore.. 



6. Tubes of medium size ; pileus large and tough, margin not ciliate. 3. H. daedalea. 

 Tubes large, mouths 1-2 mm. broad and 3-5 mm. long. 7. 



7. Margin much lobed and fissured at maturity. 4- H> Wihonii. 

 Margin entire. 8. 



8. Pileus small, 5 cm. in breadth. 5. H. hispidula. 

 Pileus large, 10 cm. in breadth. 6. II. princeps. 



9. Surface not tessellated. IO - 

 Surface tessellated. Il - 



10. Tubes large, the mouths I x 4 mm., becoming radially confluent and gill-like ; con- 



text only partially translucent. 7- H. fragilis. 



Tubes small, the mouths about half as large as in the preceding and not becoming 



confluent; context thinner, wholly translucent. 8. H.floridana. 



11. Pileus small, thin and fragile, the surface minutely checkered. 9. H. tessellatula. 

 Pileus large, thick and firm, the surface coarsely checkered. 10. //. caperata. 



12. Pileus purple or purplish-brown, stipe lateral or excentric. 13- 

 Pileus brown, stipe distinctly central. 14- 



13. Tubes merulioid. w. II. brunneola. 

 Tubes of normal length. 12. II. purpura seem. 



14. Margin entire. \-$. H. portoricmsis. 

 Margin ciliate. H- H- honduremis. 



