1922] Essig: Morpholagy of Schizophyllum commune Fries 449 



This paper is presented in an effort to give a more accurate and 

 complete description of the sporophores; a description of the micro- 

 scopic structure of the hyphae which go to make up the sporophores 

 and the vegetative mycelium ; an account of the origin and develop- 

 ment of the gills as found in specimens growing in the field at Berkeley, 

 California ; and a report on the economic aspects of the fungus. 



According to Saccardo (1887-1895), there are twelve species of 

 Schizophyllum, all of them being tropical or subtropical except S. 

 commune Fries, which is distributed throughout the northern and 

 southern temperate zones. Hennings (1898) stated that all of the 

 twelve forms described probably constituted only two or three distinct 

 species, and this view seems to the writer to be more nearly correct. 

 The original work reported in this paper is confined entirely to ScJiizo- 

 phyllum commune Fries,^ but in the table of geographical distribution 

 and the list of host plants reference is made to the genus as a whole, 

 as it is extremely difficult to distinguish between the one species of the 

 temperate zones and the several tropical species described. 



II. MATERIAL AND TECHNIQUE 



The sporophores studied came from three sources: 



1. Decayed wood in the field. 



2. Decayed wood kept in moist chambers in the laboratory. 



3. Specimens from the Herbarium of the University of California. 

 The specimens obtained from the field were collected over a period 



extending from September, 1917, to February, 1920. They were 

 found growing under natural conditions upon the wood or bark of 

 Acacia sp., Quercus agrifoUa, and, UmhellulaHa calif ornica. In all 

 several hundred specimens have been collected, ranging in age from 

 apparently a few hours to two years, and in size from less than 1 mm. 

 to 5 or 6 cm. in diameter. More than a hundred specimens of very 

 young sporophores were obtained during the autumn of 1919 from a 

 single log of Vmhellulana partly imbedded in gravel along a small 

 creek near the laboratory. 



As an experiment short sections of small trunks and branches of 

 trees infected with Schizophyllum were placed in shallow pans of water 

 and covered with bell jars. Air was admitted by supporting the bell 



1 For a complete list of synonyms see Greville (1824) and Murrill (1915). 

 The most important are Agaricus alneus Linnaeus, SchizophyUum aJneum Schroeter, 

 SchizophyJJus alneus Murrill. 



