The Origin and Development of the Apothecium etc. 
415 
observed the same raethod of ascus formation in Acetabula leucomelas. 
In Peziza catinus (Guilliermond, 45), the ascns arises from a hypha 
wliose terminal cell is uninucleate and wliose next one or two cells are 
binucleate. Tlie subterminal cell grows out into a brauch into which the 
two nuclei migrate and in w T hich they later fuse to form the ascus nucleus. 
In the young fruit bodies of Peziza stevensoniana Harper (48) found that 
asei may arise from the terminal cell and from the second cell below 
this, the cell between remaining sterile, probably because of insufficient 
nutrient material. 
I have described the young ascus as containing two nuclei which 
later fuse to form the primary nucleus of the ascus. Dangeard (24) 
discovered the fusion of two nuclei in the ascus of Peziza vesiculosa and 
several other ascomycetes. The same phenomenon has been noted by 
all later students of the group. In Peziza stevensoniana , Harper (48) 
described and figured the primary nucleus of the ascus as the resiüt of 
the fusion of four nuclei. I have found no evidence of a connection be- 
tween the masses of chromatin and a central body such as Harper (52) 
has described for Phyllactinia. 
Functional sexuality in the ascomycetes. 
As to the sexual nature of the structures which I have described, 
my results in a general way confirm those of Stahl, Baur and Darbi- 
shire. The published results of the study of ascomycetes in the last 
decade have shown that “reduced fertilization” in one form or another 
may possibly be quite widespread among this group of fungi. With the 
exception of certain lichens, very few of the higher ascomycetes have 
been found by all who have investigated then to have functional sexual 
Organs. In the mildews having uninucleate sex organs there can be no 
doubt that there is a fusion of male and female nuclei. Harper (47, 49, 
52) has described these in such detail and with so many convincing figures 
that there seems to be no reason for doubting a fusion of antheridial and 
oogonial nuclei. Harper’s work on Sphaerotheca (47) has also been 
confirmed by Blackman and Fraser (10). However, cpiite recently Winge 
(88) in a very short paper with few figures Claims that although the 
antheridium is formed, the male nucleus does not enter the oogonium. 
He finds the nucleus in the antheridium after the oogonium has become bi- 
nucleate. This is in agreement with the observations of Dangeard (24 a) 
in 1897. Winge’s (88) figures are certainly not convincing, and it seems 
probable that he may have mistaken the disintegrating cytoplasm 
of the antheridium for a nucleus. Pyronema, which has been so fully 
