THE DISCOMYCETES OF EASTERN IOWA. 235 



between all of these forms. The spherical spores are gen- 

 erally disposed in one row in the ascus, those of an elliptical 

 form in one, two, or four rows, or they may be irregularly 

 arranged as in many species of Ascobolus. The elliptical 

 spores are generally parallel or oblique with reference to the 

 ascus. The fusiform spores may be in one or two rows and 

 are generally nearly parallel with the ascus and those of a 

 linear form are side by side and also parallel or nearly so. 



The spores may be free in the ascus or imbedded in a 

 gelatinous substance. In several species each individual 

 spore is imbedded in this way, and in one genus, Saccobolus, 

 the eight spores are closely united and the whole number 

 imbedded in a block of gelatine, in which they are ejected 

 from the ascus, still remaining united after being ejected. 



Externally the spores may be smooth or marked in various 

 ways. The markings may be the form of minute spines 

 which are sometimes long, and sometimes very short, or they 

 may form larger wart-like structures when the spores are said 

 to be verrucose. In still other cases the spores are marked 

 by elevated ridges arranged so as to form various patterns. 

 In this case the spore is said to be reticulate. 



Internally the spores are colored, transparent or hyaline, or 

 granular, and in many cases there are one or several trans- 

 parent drops, the number being quite constant with the 

 different species, and the spore is then said to be guttate or 

 guttulate. In many cases, especially when the spores are 

 long and slender, they are divided by cross walls into several 

 cells, and are then septate. 



One of the most interesting points in connection with the 

 sexual fructification of the discomycetes is the manner in 

 which the spores are ejected from the ascus at maturity. If 

 fresh material of almost any of the common species, such as 

 Peziza aurantia Pers., PI. VIII, Fig. 1. be placed in a moist 

 chamber and left for some time, on suddenly lifting the 

 bell jar, a cloud of spores will be seen to issue from the 

 hymenium in such numbers that the fungi are often said to 



