116 ASCOMYCETES AND RHODOPHYCEA. 
fuse, but this fusion does not, as previously stated for Spherotheca, 
represent a sexual process, 
It will thus be seen that the process of fecundation in Pyronema 
consists in the union of multinucleated gametes and in the fusion of 
their nuclei respectively in pairs. Here as in all other plants, whether 
possessing uninuclear or multinuclear gametes, the fact of prime 
importance is the fusion of the sexual nuclei, the cytoplasm playing 
perhaps an incidental and secondary réle. The fusion of numerous 
pairs of sexual nuclei in the egg-cell is after all not so remarkable since 
the significance and final result is the same as in the case of uninuclear 
gametes. We may upon strong grounds conclude with Harper that 
‘*this aggregation of nuclei at the time of fertilization seems to be 
simply a provision for the pairing of male and female nuclei with the 
Fic. 44.—Group of 3 pairs of sexual organs of Pyronemea in surface view.—(After Harper.) 
greatest certainty and despatch.” The cell, considered as a morpho- 
logical and physiological unit, is just the same no matter whether it 
possesses one or many nuclei, and in this respect there seems to be no 
good reason for regarding a ‘‘coenocyte”’ as a tissue. 
BATRACHOSPERMUM., 
As representing the sexual process in the Rhodophycee I have 
selected Batrachospermum and Dudresnya. Batrachospermum is 
selected on account of the comparative simplicity of the spore-fruit 
development, and because the fusion of the sexual nuclei, as observed 
by Osterhout (1900), leaves not the slightest doubt as to the exact 
nature of a sexual reproduction. The classical object, Dudresnya, 
affords an illustration of a complex series of phenomena following 
fecundation, which has, until recently, been regarded as representing 
several separate sexual acts. 
