PILEATE HYDXACEAE FROM IOWA 419 



4. M. CORDIFORMIS Scop. (Hiidnum Erinaceus Bull.) 



A common species, at least locally, which differs from our 

 oilier species of the genus in its unbranched, tubercular pileus 



and shaggy spines which give the fungus a rather pronounced 

 heardlike appearance. This fungus cannot well be confused 

 with any other Iowa species. On living and recently cut oak, 

 causing a serious heart rot which finally results in a hollow 

 trunk. All our material appears to be local. 



Johnson county (Macbride, Shimek, Wilson). 



III. STECCHERINUM S. F. Gray. 



A group of species of exceptional variability in form and 

 habit, ranging from pileate to laterally sessile, or even resupi- 

 nate. The spores are smooth and light-colored, while the con- 

 text is tough and fibrous. Always on wood. We have three 

 species. i 



5. S. OCHRACEUM (Pers.) S. F. Gray. (Hydnum oehraceum Pers.) 



A common and variable species which appears to be confined 

 to dead oak wood. The sporophores may be single or imbricate, 

 often confluent, sessile to decurrent or even resupinate. The 

 surface of the cap suggests a polypore of close relationship with 

 Polyporus pergammus, while the ocher-colored spines are equally 

 characteristic. This is the only species which the writer has 

 found twice referred to in literature as having been collected in 

 Iowa. Banker 6 records it among the species which Holway col- 

 lected, and Shimek 7 records it from the Okoboji region. These 

 citations would indicate that it is well distributed throughout 

 the state. 



Iowa City. Johnson county, (Macbride. Wilson) ; Okoboji re- 

 gion, Dickinson county (Shimek). 



6. S. ADUSTUM (Schwein.) Banker. (Hydnum adustum Schwein.) 



A very peculiar and interesting species which shows a wide 

 range of variability in form and habit. The hymenophore may 

 be sessile or stipitate, separate or more or less laterally con- 

 nate, or even developing a '•two-story" habit of imbricate pelei. 



"Mem. Torrey Club, 1906, 12, 1-'.". 

 7 Loc. cit, p. 54. 



