Murrill: Polyporaceae of North America 483 



1904 



20. ABORTIPORUS Mum Bull. Torrey Club 31 : 421. 



Type : Boletus distortus Schw. 



Hymenophore annual, tough, humus-loving; stipe normally 

 central, often obsolete; context yellowish-white, duplex, spongy 

 above, woody below, tubes thin-walled, mouths polygonal ; spores 

 subglobose, smooth, hyaline. 



Species : A. distortus (Schw.) Murr. [See Bull. Torrey Club 

 31: 421, 422. 1904]. 



21, Microporellus gen. nov. 



Type : Polyporus dealbatus B. & C. 



Hymenophore thin, annual, epixylous, usually flabeHiform, 

 stipitate, the stipe variously attached and sometimes much re- 

 duced ; surface anoderm, multizonate ; context thin, white, fibrous, 

 rigid and fragile when dry ; tubes very minute, regular, thin- 

 walled, fragile when dry; spores smooth, hyaline. 



Synopsis of tlie ^(ortti American species 



Plants Avhite or pale brownish, the color not changing when dry. M. dealbatus. 



Plants lurid, becoming black when dry, M. holotephrus, 



+ 



Microporellus dealbatus (B. & C.) 



Polyporus dealbatus B. & C. Ann. Mag. Nat. Hist. II. I2 : 432, 



1S53. 

 Polyporus mutabilis B. & C. Ann. Mag. Nat. Hist. II. 12: 433. 



1853. 

 Polyporus petaliformis B. & C. Jour. Linn. Soc. Bot. lO : 107. 



1868. 



J 



307 



1868. 



Polyporus Ravcnelii ^. %i Z. QxtvWXtd. 1:38. 1872. Polystictus 

 cretatus Cooke, Trans. Bot. Soc. Edinburgh 13: 137. 1878. 

 This remarkably variable plant was originally described from 

 the collections of Curtis in South Carolina, and has since been 

 published by the same authors under several different names. 

 The types at Kew show abundant variations, but no good charac- 

 ters for specific separation. The species ranges southward to the 

 West Indies and into South America, where it has doubtless 

 received other names. 



Collections are at hand from South Carolina, Ravcncl ; Georgia, 

 Picker; Y\on<^3., Ravend ; Louisiana, Langlois ; KX^h^xu^., Peters , 



