THE DISCOMYCETES OF EASTERN IOWA. 239 



The process of spore-dispersal may also be studied with the 

 low power of the microscope in almost any of the members of 

 this family. In Ryparobius crustaceus (Fckl.) Relim., PI. 

 XVII, Fig. 11, the asci have been seen to protrude very much 

 until the spores have been ejected and then to gradually 

 retract toward their original position. 



DeBary in his Morphology and Biology of Fungi, p. 92, 

 describes this process in the following words: " When the 

 asci are ready to eject their spores they are very much 

 extended and their broad club-shaped apex rises considerably 

 above the surface of the hymenium; this led to the erroneous 

 idea which was reproduced by Boudier, that the asci became 

 detached from their point of insertion and wandered up 

 among the paraphyses; they really remain firmly attached as 

 in all the rest of the Discomycetes. The projecting asci are 

 moreover distinctly visible to the naked eye in the larger 

 species as dark points, by reason of the dark violet-colored 

 spores in their apices. These points disappear at the moment 

 of dusting, because the spores fly off and the empty tubes are 

 drawn back beneath the surface of the hymenium. Older 

 observers were led by these appearances to the mistaken 

 notion that the entire asci were ejected from the hymenium 

 and hence the name Ascobohis." 



The habitat of the discomycetes varies with the different 

 species and seems to be quite constant in each individual 

 case. Only one of the species described in this paper is 

 parasitic, Mollisia dehnii (Rabenh.) Karst, PI. XXIII, Fig. 

 1. This plant occurs on living plants of Potentilla norvegica 

 and grows in such numbers as to almost completely cover the 

 stems and leaves, those on the leaves being found on or near 

 the veins. 



The remaining forms are saphrophytic and occur on nearly 

 every kind of organic matter, such as decaying wood, leaves 

 and stems of herbaceous plants, damp soil which is mixed 

 with organic material, charcoal, ashes, old cloth, paper, etc. 



Ascophanus testaccus (Moug.) Phill. PI. XIII, Fig. 1, is 



