1922] Essig: Morphology of Schizophyllum commune Fries 463 



3. TAXONOMIC INTEEPEETATION OF THE STRUCTURE AND 

 DEVELOPMENT OF THE SPOROPHORES 



It was early observed that while Schizophyllum was presumed to 

 possess gills, the structures were unique among the members of the 

 Agaricaceae. Consequently considerable difficulty has been experi- 

 enced among systematists in associating this genus with the other 

 members of the family from which it is so distinct. 



Fayod (1889) believed it to be precisely like Pamis, except that 

 in Panus the gills were entire. He classified them under the tribe 

 Panoides, and noted a similarity in the geographical distribution of 

 the two genera. Hennings (1898), following Saccardo (1887-1895), 

 placed Schizophyllum in the tribe Schizophylleae with Rhacophyllus, 

 Oudemansiella, and Pterophyllus, but stated that the other genera do 

 not seem to belong to this group. Murrill (1915) put it in the tribe 

 Agariceae and subtribe Lepiotanae along with Marasmius, Lepiota, and 

 other white-spored members of the Agaricaceae. 



All these writers have based their classification upon the assump- 

 tion that the hymenium in Schizophyllum is borne upon the surface 

 of lamellae. Since this is not the case — for the hymenophore while 

 quite complex in structure bears a smooth h^Tnenium — the fungus 

 should be placed in the family Thellephoraceae. In this family it 

 resembles Cyphella in the organization of the sporophores, for, in this 

 genus, according to De Bary (1887), the hymenium lines the inner 

 and lower surfaces of a funnel-shaped sporophore, the stipe being 

 attached to the opposite side of the pileus from the hymenium (fig. 16, 

 pi. 52). The early stages in the development of Schizophyllum com- 

 mune and Stereum hirmitum,, likewise, have much in common. In the 

 later stages, however, the hymenium of Stereum hirsutum remains 

 entire, and bears no resemblance to the much divided hymenium 

 of Schizophyllum commune. Only in the genus Cladoderris is there 

 anything comparable to the hymenial plates of Schizophyllum. Clado- 

 derns is somewhat similar to Stereum., but differs in possessing radiat- 

 ing, branched ribs upon the hymenial surface. Some species of Clado- 

 derris have the pileus margin much incised. The representatives of 

 the genus Cladoderris are chiefly tropical, and are known to the writer 

 only through descriptions and illustrations. From these it seems that 

 there is only a difference in degree between the splitting of the pileus 

 margin in sporophores of Cladoderris infundihuUformis Fries (cf. 

 Hennings, 1898) and the marginal division in fruit bodies of Schizo- 

 phyllum commune. 



