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Some Species of Nummularia Common in Indiana. 



Claude E. O'Neal. 



The difficulty of distinguishing the various species of Nummularia, 

 and even the genus itself from the genus Hypoxylon, is quite evident to 

 anyone who has made any attempt at their classification. In a paper en- 

 titled "A Monograph of the Common Indiana Species of Hypoxylon",* C. 

 E. Owens, by the aid of plates and an artificial key, sets forth the charac- 

 teristics of the common species of the latter genus. The purpose of this 

 paper is to do a similar work with the available species of the genus 

 Nummularia. 



In the study of Nummularia, attention is first directed toward the 

 stromata, which appear as blackish or brownish incrustations on the dead 

 trunks and limbs of our common deciduous trees. In form, the stromata 

 vary greatly, but in general, they belong to two types, one of which may be 

 described as cup-shaped, and the other as convex. The former type is 

 usually orbicular or elliptical in shape, while the latter may be either orbi- 

 cular, elliptical, or broadly effused with an irregular outline. 



The stromata arise beneath the epidermis of the substratum where 

 they may remain concealed for some time, but sooner or later, the epidermis 

 is broken through and the spore-bearing surface is exposed. Sometimes in 

 old specimens the entire epidermis may be removed and the erumpent 

 characteristic overlooked. In some cases the entire cortex may decay and 

 fall away, leaving the stromata standing out on the decorticated surface. 

 Again, some of the more resistant ones may be found in good condition (in a 

 log that is ready to drop to pieces from decay. 



In width the various Indiana species range from a few millimeters in 

 the cup-shaped forms to several centimeters in the broadly effused types. 

 The thinnest ones that the author has found have been about one-half milli- 

 meter thick while some of the cup-shaped forms may have a thickness of 



'Proceed. Ind. Acad. Sci. 1911, p. 291. 



