IOWA DISCOMYCETES 125 



the ash is native and its distribution is probably coextensive 

 with that of the host. 



In North Dakota this species has been observed in great quan- 

 tities. One collection on branches of Xantkoxylum americmum 

 seems identical both in internal and external characters. 



Hysterographium mori (Schw.) Rehm,, Ber. Natuhr. Ver. 

 Augsburg 26 : 90. 1881. 



Plate 41, f. ii. 



Eystt Hum mori Schw.. Trans. Am. Phil. Soe. II. 4: 244. 1832. 



Plants erumpent-superficial, elliptical to linear or cylindrical, 

 1 to 3 mm. long, and .5 to 1 nun. wide, mostly straight or lying 

 parallel with the grain of the wood, gregarious or crowded, often 

 covering the substratum more or less longitudinally striated; 

 lips mostly closed at first, finally more or less spreading; asci 

 cylindrical, about 100 by 12/*, 8-spored ; spores 1-seriate or more 

 or less crowded together above, ovate, smaller below, 3 to 5- 

 septate, a little constricted at the middle septum, cells divided 

 by a longitudinal septum, brown, 15 to 25 by 7 to S/x. 



On decorticated wood of various kinds. 



This is a very common, abundant and variable species, occur- 

 ring on nearly every kind of wood. Specimens found commonly 

 on old wood of butternut conform well with the description of 

 H. cinerascens Schw.. but I can find no reliable character by 

 which it can be distinguished from the present species. 



BIBLIOGRAPHY 



Auerswald, B., Sarcosphaera Awd. novum genus Discomycetum. Hed- 



wigia 8: 82-S3. 1869. 

 *Afzelius, A. De vegetabilius Sueeanis observations et experimenta. 



Yet. Acad. Hanril. 1785. 

 De Albertini, J. B. & Schweinitz, L. D. Conspectus Fungorum in Lusa- 



tia? superioris agro Niskiensi crescentium, e methodo Persooniana. 



1805. 



*Literature not accessible to the writer, citations given on other 

 authority than our own. 



