122 



Mycologia 



In such forms as A. Winteri and A. furfuraceus fully developed 

 normal ascogonia can be found on hyphae where there is no indi- 

 cation whatever of a structure which in any way resembles an 

 antheridium. I am convinced that these species do not possess 

 morphological antheridia, although fertilization may take place 

 in some other fashion. There can be no question, however, of 

 the necessity for both kinds of sex organs in A. magnificus. 

 This cannot be over-emphasized, since many students of the Asco- 

 mycetes are inclined to accept the view that sexuality exists in 

 only a few forms like Pyronema and the powdery mildews. 



The primordia are visible even without a hand-lens and it is 

 possible to determine within a few hours just when they will 

 first make their appearance in the Petri dish culture. Flem- 

 ming's weaker fluid is then poured into the dish which can be set 

 aside for examination at leisure. The circle of agar can be 

 floated out into a large battery jar, where it can be washed to 

 remove the fixative previous to mounting the primordia in glycer- 

 ine jelly. It is much better to study them while they are covered 

 with Flemming's if one is interested in tracing the hyphal con- 

 nections with them. An oatmeal agar or a potato agar is favor- 

 able for the production of large numbers of papulospores or 

 large amounts of mycelium, but the starchy media should not be 

 used if ascocarps are desired. I have dissected a very large 

 number of primordia and have not found a single case where a 

 normal, vigorously growing ascogonium was not accompanied by 

 an antheridium and this is a pretty good indication that there is 

 one species of Ascobolus at least in which the sexuality has not 

 been lost or reduced. 



We may now turn to the asexual method of reproduction of 

 this species. Many common species of Ascobolus in Europe and 

 America are, so far as reported, devoid of asexual spores. A. 

 parasitica, described by Van der Wolk (14), is said, on little 

 evidence, to possess a Sclerotium stage as well as a Rhizostil- 

 bella stage. I have described the curious spore-like bodies that 

 grow in pure cultures of A. carbonarius (5). The ascogonia 

 arise directly from certain of these "spores," but further study 

 will be necessary to settle the question as to the exact nature of 

 the others. 



