1926] 



BURT THELEPHORACEAE OF NORTH AMERICA. XV 213 



and Canada from Massachusetts westward to the Pacific states. 

 May to November. Occasional. 



It has been necessary to depart from the conflicting concepts of 

 C. lacteum, and base the species on the presumably oldest existing 

 specimen collected and determined by Fries and preserved in his 

 herbarium under the name of Thelephora lactea. Other and more 

 recent specimens were referred by Fries to Corticium lacteum, the 

 genus Corticium not being used by Fries until the publication of 

 his 'Epicrisis.' These more recent specimens are of various 

 species as might be expected, for the exact methods of the present 

 day in the study of resupinate Hymenomycetes were not then 

 used, and it is probable that these later specimens have caused 

 the confusion in current concepts of C. lacteum. It is fortunate 

 that one of these later specimens, named by Fries, agrees with 

 the original specimen, is in better condition than the original 

 specimen, and is preserved in Kew Herbarium where it is con- 

 venient for comparison. C. lacteum, as understood from these 

 specimens, belongs in a group of species of similar aspect having 

 globose spores about 6 \l in diameter. The other members of this 

 group are C. radiosum, and C. abeuns. C. pellicular 'e has the same 

 aspect as the others named but its spores are not globose. When 

 one knows any one of the above group of species the other species 

 should be readily recognized as they are found, for C. lacteum has 

 rather coarse, loosely arranged, more or less granule-incrusted 

 hyphae, and lacks gloeocystidia and vesicular bodies; C. abeuns 

 has wholly immersed gloeocystidia of the usual kind; and C. 

 radiosum has vesicular organs which are at first like those of C. 

 polyonium but become much more inflated and with highly at- 

 tenuated wall, and finally perhaps are shown only by vesicular 

 spaces between the massed hyphae. 



Specimens examined : 

 Sweden: type, under the name Thelephora lactea (in Herb. Fries); 



Svex. Soderm., Lindblad, determined by E. Fries as Corticium 



lacteum (in Kew Herb.) ; Stockholm, L. Romell, 114, 179, 327. 

 Finland: Mustiala, P. Karsten, comm. by Karsten under the 



name Corticium pellicula Fr.? 

 France : Fautrey, determination as Corticium lacteum approved by 



Patouillard for Lloyd, comm. by C. G. Lloyd, 4368. 



