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A ]\[ONOGRAPH OP THE COMMON TnDIANA SpECIES OF HyPOXYLON. 



Charles E. Owens. 



It is the purpose of this iiaper not to present an exliausti^ve treatise 

 on the genus Hjiioxylon. hut to give a brief account of tlie habit and 

 habitat of these fungi as the writer has observed them, together with a 

 key to the species which have been collected in this State. Descriptions of 

 the species covered by the key have also been included. 



The Hypoxylons, like most other fungi, have a vegetation phase which 

 grows hidden in the sulistratum, and a fruiting phase which grows on 

 the surface of the host for the purpose of facilitating the dissemination of 

 the spores. The essential part of this fruiting body consists of from one 

 to many perithecia which contain the spore-bearing asci. The perithecia 

 are usually aggregated in clusters and imbedded in a carl)onaceous crust 

 known as a stroma. The stroma is more or less conspicuous and varies 

 greatly in form and size. Sometimes it may take the form of a broadly 

 effused crust several inches or even many feet in extent ; again it may be 

 a globose, subglobose, or hemispherical structure varying in size from a 

 single perithecium approximately 1 mm. in diameter, to a large stroma 

 1 to 2 cm. in diameter and containing numerous perithecia. The perithecia 

 are usually arranged peripherally in a single, regular or irregular layer. 

 Sometimes, however, they are crowded into several more or less irregular 

 layers, so that the spore-bearing layer of the stroma may be several times 

 the thickness of a single perithecium. The stromata ai'e usually of a 

 carbonaceous nature, but sometimes they are woody or corky-fibrous. The 

 color of the substance is generally dark-brown or black ; while that of 

 the surface exhibits a range from whitish or gray, through various shades 

 of red, ferruginous and purple, to black. 



Without exception, the species of this genus are saprophytic and live 

 Vipon the dead trunks, branches and rotten wood of various kinds of trees. 

 They prefer the shade and moisture of the woods and are seldom found in 

 the open where they would be exposed to direct sunlight for a large part 

 of the day. Certain species, however, are sometimes found around the 

 edge of woodlands where they are not shaded at all times. This is es- 



