29O NATURAL HISTORY BULLETIN. 



externally smooth. Asci clavate, 8-spored; spores elongate, 

 curved, i-celled, often in 2 rows. Found on the stems of 

 plants. 



Two species have been collected, one of which is sometimes 

 included in another genus. 



KEY TO THE SPECIE.S. 



a — On living plants of Potentilla . . . M. dehnii 



a — On decaying plants of Polygonum . . . 31. polygoni 



Mollisia polygoni {Lash) Gill. 

 Plate XXIII, fig. n. 



1888 Yeziza polygoni Farlow and Seymour, Fung, of U. S. , II, p. 92. 

 L889 Moltisia polygoni Saccardo, Sylloge Fung., VIII, p. 322. 

 L897 Mollisia polygoni Engler-Prantl, Pflan. Famil., I, p. 212. 



Gregarious, sessile, at first hemispherical, then expanded, 

 about i mm. in diameter, dark greyish, often lighter when dry; 

 hymenium slightly concave or plane; asci clavate, 7 to 9 by 2 

 microns; sporidia fusiform, elongated on one side, often gut- 

 tulate; paraphyses filiform, slender. 



Habitat — On stems of Polygonum in wet places among 

 weeds; Lafayette, Indiana and Iowa City, Iowa. 



These plants have been found almost completely covering 

 decaying stems of Polygoiium in woods near Iowa City. The 

 plants are very small and generally dark colored but some- 

 times yellowish. These plants seem to be especially adapted 

 to the stems of this host plant as they have not been found on 

 plants of any other species. 



Mollisia dehnii (Rabenh.) Kctrst. 

 Plate XXIII, fig. 1. 



1888 Yeziza dehnii Farlow and Seymour, Fung, of U. S. , 8, p. 35. 

 INN' > Mollis ia dehnii Saccardo, Sylloge Fung., VIII, p. 325. 



Gregarious or crowded, sessile or with a very short stem, 

 about 1 mm. in diameter, dull lead color; hymenium at first 

 concave then plane; asci clavate; sporidia elongate, straight 



