482 CLASS BASIDIOMYCETEAE 



the same family under the name Irpiciporus. Miller (1933) regards 

 Hydnochaete, Sistotrema, Irpex, and Echinodontium, whose teeth are 

 formed by the breaking up or unequal growth of the pore walls, as 

 properly placed in that family. Hydnum, as recognized by Fries in 1821, 

 included all of the genera now included in the family as well as some of 

 the above mentioned ones that may eventually have to be placed else- 

 where. In the following the generic distinctions of Miller (1933) are 

 followed in the main. 



Grammothele Berk. & Curt, is resupinate with its porose-reticulate 

 surface covered with numerous small warts over which the hymenium 

 extends. Caldesiella Sacc. is in habit much like TomenteUa of the Thele- 

 phoraceae, but is covered with soft conical spines or teeth. The spores are 

 colored and rough. Asterodon Pat. is similar but has dark, simple or 

 stellately branched, setae, and the smooth spores are subhyaline. Gran- 

 dinia Fr. is also resupinate and resembles Corticium from which it differs 

 in the development toward maturity of hemispherical, cylindrical or 

 subulate warts or spines, covered with hymenium. Cystidia are lacking 

 and the spores are hyaline and smooth or roughened. Odontia Pers. differs 

 from the preceding by the presence of cystidia. It therefore resembles 

 Peniophora except for the conical to subulate or cylindrical spines. 

 Oxydontia Miller lacks cystidia and has long subulate and conspicuous 

 teeth. It is resupinate or effused-reflexed. This is the genus called Ada, 

 Karst., an untenable name because of its prior use for one of the Rosaceae. 

 Radulum Fr. (including Phaeoradulum Pat.) is resupinate or reflex, with 

 coarse, blunt, irregularly scattered or confluent teeth. Spores hyaline or 

 light-colored. Phlehia with hymenium covered with more or less notched 

 wrinkles is sometimes placed in this family. These last four genera suggest 

 how the Hydnaceae may have arisen from the resupinate Thelephoraceae 

 in which the smooth hymenium often shows little warts or even pro- 

 jecting bundles of hyphae. However, these latter are not covered by the 

 hymenium. Mucronella Fr. is essentiall}'' a cluster of subulate teeth 

 arising from a fugacious mycelium. 



The following genera are attached laterally or have stalks. Steccherinum 

 S. F. Gray is sessile or substipitate and laterally attached. It has terete 

 or flattened spines and develops cystidia. The spores are white and small. 

 It is wood inhabiting. Auriscalpium S. F. Gray is laterally stipitate and 

 has short subulate spines with scarcely differentiated cystidia. Growing on 

 cones of conifers. The following three genera are centrally stipitate with 

 subulate spines, and grow on the ground: Dentinum S. F. Gray, fleshy, 

 pale, spores white and smooth, subspherical; Hydnum L. emend. S. F. 

 Gray, fleshy, dark-colored, spores subspherical, angular or echinulate, 

 brown; Calodon Qu(51. (Hydnellum and Phellodon of Karsten), fibrous, 



