DUDRESNYA. 119 
development of the spore fruit from the egg-cell. Such a doctrine 
has, of course, the value of mere conjecture only. 
The fusion nucleus increases in size and shows clearly a single large 
nucleolus and a well-defined threadwork in which are held distinct 
chromatin granules, The trichophore now begins to send out one or 
more protuberances (Fig. 46, E). The fusion-nucleus divides, and 
one of the daughter-nuclei passes into a protuberance which is then 
cut off by a transverse wall. By a repetition of this process many 
cells are produced, each containing a nucleus which is a descendant of 
the fusion-nucleus. Each of the cells thus borne by the carpogonium 
will give rise to gonemoblast filaments, whose end cells form the 
carpospores. 
DUDRESNYA, 
From the foregoing it will be seen that the sexual process and the 
subsequent development of the fecundated egg in Batrachospermum 
are comparatively simple, but in the vast majority of the Rhodophycee, 
because of the peculiar structure of the thallus, the details in these pro- 
cesses are extremely difficult to follow even in the most favorable cases. 
In the better known representatives, such as Dudresnya and the 
simpler Callithamnion, the carpogonium does not give rise to the 
spore fruit (cystocarp), as in Memalion (Wille) and Batrachosper- 
mum, but from each carpogonium whose egg-cell has been fecundated 
a number of filaments (two or three in Dudresnya) are developed, 
which fuse with certain vegetative cells, and from which, in connection 
with a part of the filament, the cystocarps are developed. These fila- 
ments are the odélastema filaments of Schmitz (’83) and the sforo- 
genous filaments of Oltmanns (’98). The vegetative cells with 
‘which these fuse are known as auxzézary cells or brood cells. This 
fusion of the sporogenous filaments with auxiliary or brood cells was 
regarded by Schmitz and his followers as a second fecundation, a 
phenomenon unparalleled among plants, and which, as Schmitz put it, 
was contrary to all tradition: ‘‘ Einen zweimaligen Befruchtungsact 
im Entwickelungskreise einer einzelnen Species anzunehmen, dagegen 
straubt sich zur zeit die botanische Anschauung vollstindiger, das 
widerspricht aller Tradition.” 
The recent researches of Oltmanns (’98) seem to show what is, in 
all probability, the true significance of the fusion of sporogenous fila- 
ments and auxiliary cells. He maintains that the fusion of the sporoge- 
nous filament, or a cell of the same, and an auxiliary cell is not a 
sexual process, since it is only a cytoplasmic and not a nuclear fusion 
that takes place. Furthermore, the nuclei of the carpospores, as in 
