224 NATURAL HISTORY BULLETIN 



KEY TO THE SPECIES. 



Spores large, more than 25ix long. 



Spores 25 to 30 by 8 to 10/j., on bark of oak. . . H. kansense. 



Spores 30 to 40 by 15 to 28^, on branches of ash. H. fraxini. 



Spores small, less than 2oix in length. . . . . . S. mori. 



Hysterographium kansense Ellis & Everhart, Erythea 2 : 22. 

 1894. 



Plate 41, f. I. 



Perithecia scattered, oblong, ends subacute, 1 to 1.25 by .dfi, 

 black, subconchiform, longitudinally striated, lips closed or 

 slightly open so as to leave a narrow cleft; asci clavate, 80 to 

 110 by 12 to 14/i,, 8-spored ; spores 2-seriate or partially so, ovate 

 or fusoid, 7 to 9-septate, with most of the cells finally divided 

 by a longitudinal septum, brown, 25 to 30 by 8 to 10;u. 



On bark of various species of Quercus. 



This species has been collected several times by the writer 

 and on the bark of several different species of oak. It was at 

 first taken to be H. stygium Cooke, but comparison with an au- 

 thentic specimen of this species shows the spores to be much too 

 narrow. This difference is also mentioned in the original de- 

 scription of the species. Iowa material conforms well with the 

 type of the species to which it is referred. 



Hysterographium fraxini (Pers.) De Not., Giorn. Bot. It. 2: 

 22. 1847. 



Plate 41, f. III. 



Hysterium fraxini Pers., Syn. Fung. 100. 1801. 



Plants scattered or gregarious, erumpent, elliptical, black, ob- 

 tuse, 1 to 1.5 mm. long, .5 to .75 mm. wide ; lips swollen, smooth, 

 partially open so as to expose the elongated hymenium; asci 

 clavate, rounded above, 150 to 200 by 30 to 40ju,, 8-spored ; spores 

 2-seriate, oblong-elliptical, scarcely constricted in the middle, 7 

 to 9-septate and muriform, dark brownish, 30 to 40 by 15 to 18/x. 



On dead branches of Fraxinus. 



This species occurs in abundance on the dead branches and 

 twigs of various species of Fraxinus before or after the bark is 

 removed. The species appears to be common in localities where 



