REPRODUCTION. 621 



of this Ascomycete are two quite similar hyphal branches 

 which are closely coiled round each other, and which coalesce, 

 after the absorption of the intervening walls, at their apices. 

 The product of coalescence is, in the first instance, a large 

 rounded cell. So far the process and its product resemble 

 those of the Mucorini, and were this all the process would be 

 termed conjugation, and the product a zygospore. But the 

 cell in question is not a zygospore ; it does not, like a zygospore, 

 germinate and give rise to a new plant. A process of cell-for- 

 mation goes on within it, as a consequence of which eight free 

 cells are produced, which, on being liberated, germinate. It is, in 

 fact, these eight cells which are the spores ; they are termed asco- 

 sporeS) and the large cell in which they are developed the 

 ascus. 



The peculiar nature of this mode of the sexual process 

 demands a brief explanation. We have here a case in which 

 no process of cell-formation takes place in either of the sexual 

 organs as a preliminary to the sexual process. It is only 

 when the protoplasmic contents of the two sexual organs have 

 fused that cell-formation takes place; and inasmuch as the 

 cells then formed consist of protoplasm derived from the 

 two sexual organs, they are not sexual reproductive cells, 

 but are sexually produced spores ; each of them is, in fact, 

 physiologically the equivalent of a zygospore or an oospore. 



The sexual process is essentially of this nature in many 

 Ascomycetes, though the sexual organs differ from each other 

 externally, thus affording an indication of differentiation of 

 sex which is wanting in Eremascus. In Pyronema (Peziza) 

 confluens, according to the descriptions of De Bary, Tulasne, 

 and Kihlmann, the sexual organs are hyphse which are 

 developed close together. One of these undergoes no special 

 modification, and constitutes the male organ, the pollinodium ; 

 the other, which is the female organ, the archicarp or carpogo- 

 nium, becomes somewhat dilated, and developes at its rounded 

 free end a delicate tube which is a trichogyne. This tricho- 

 gyne becomes closely applied to the pollinodium, and, in 

 consequence of the absorption of the intervening cell-walls, 

 complete fusion of the protoplasmic contents of the pollino- 



