THE DISCOMYCETES OF EASTERN IOWA. 23 1 



lected are retained for further study and it is hoped will appear 

 in a later paper. 



In making: the determinations I wish to extend thanks to 



Dr. E. J. Durand of Cornell University for suggestions and 



exchange of material. 



Fred J. Seaver. 



Iowa City, April, 1904. 



INTRODUCTION 



The Discomycetes include all those forms of ascomycetous 

 fungi in which the fruiting surface, or hymenium, is well 

 exposed at maturity. This character distinguishes them from 

 the closely allied group, the Pyrenomycetes, in which the 

 hymenium is entirely inclosed in the perithecium, or opsn to 

 the exterior by a small aperture only. On account of the 

 peculiar cup-like form assumed by many of the plants of this 

 group in their fruiting phase, they are often called cup-fungi. 

 Ranging, as they do, in size from cups three or four inches 

 in diameter to those scarcely visible to the unaided eye, many 

 of the smaller and often more beautiful forms are seldom, if 

 ever, seen by the casual observer. 



As all other fungi, the individuals of this group are either 

 parasitic, or saprophytic; the parasitic forms being found for 

 the most part, on the stems and leaves of living plants, while 

 the saprophytic forms, which comprise by far the larger num- 

 ber, occur on almost every kind of decaying organic material, 

 where the conditions of moisture are suitable. In damp shady 

 woods, scarcely a decaying log may be found which does not 

 bear on its surface some form of discomycetes, although the 

 aid of the hand-lens is often necessary to bring their minute 

 forms into view. But although small in size, they are no less 

 perfect in structure and beautiful in appearance; their colors 

 often rivaling those of the most brilliant flowers of our gardens 

 and their microscopic sporidia being often beautifully colored 

 and delicately sculptured. 



