Wager. — The Sexuality of the Fungi. 583 
De Bary’s views, however, have been confirmed by the 
researches carried on by Harper 1 on some of the simpler 
forms of the Ascomycetes. In Sphaerotheca , for example, 
Harper finds that the organs regarded by De Bary as sexual, 
oogonium and antheridium, each contain one nucleus, and 
that the antheridial nucleus passes into the oogonium, the 
two nuclei then fusing together to form the sexual nucleus of 
the oospore. The antheridial nucleus is at first slightly 
smaller than the nucleus of the oogonium, but before fusion 
takes place it attains practically the same size. 
The fertilized oogonium (oospore) becomes surrounded by 
filaments arising from the basal cells. Then the nucleus 
divides, and a row of cells forming the ascogonial filament is 
formed ; one of these, the subapical cell, contains two nuclei, 
and from this cell the single ascus arises. This cell increases 
in size, and the two nuclei which it contains fuse together into 
one, and this subsequently divides to form the nuclei around 
which the ascospores are formed. 
Dangeard 2 , however, does not accept Harper’s results as to 
the primary sexual fusion of nuclei, although he agrees in 
general with him as to the subsequent phenomena. In an 
exhaustive paper he attempts to prove that only one fusion 
of nuclei takes place, viz. in the ascus. He affirms that the 
antheridial cell undergoes degeneration at an early stage, which 
extends both to protoplasm and nucleus; that the ascogonium 
often contains one nucleus only, even when the covering 
branches begin to surround it ; that ascogonia with two nuclei 
sometimes show a nucleus still in the antheridial cell, and 
that an appearance of fusion which he once observed was due 
not to actual fusion, but to one of the covering hyphae lying 
alongside the antheridial cell, 
From a careful examination of the figures given both by 
Dangeard and Harper, it appears to me that not only is the 
1 Harper, Die Entwickelung des Peritheciums bei Sphaerotheca Castagnei Lev. 
Ber. d. Deutsch. Bot. Ges., xiii, 1895, p. 475. Ueber das Verhalten der Kerne bei 
der Fruchtentwickelung einiger Ascomyceten. Jahrb. f. wiss. Bot., xxix, 1896, p. 655. 
2 Dangeard, La Reproduction sexuelle dans le Sphaerotheca Castagnei. Second 
Memoire sur la Reproduction sexuelle des Ascomycetes. Le Botaniste, v, 1895-6. 
