GULFWEEDS (SARGASSUM) 323 
and are borne in sex organs, which are also quite unlike. The sex 
organs are borne in hollow conceptacles, which occur in large 
numbers in the swollen tips of the branches. Each conceptacle 
opens to the exterior by a pore-like opening. In this species the 
male and female sex organs do not occur together in the same 
conceptacles as they do in some species. The odgonium is a 
large, globular, stalked cell and in this species contains eight eggs, 
but the number ranges from one to cight in other species of 
Fucus. The antheridia are borne 
on the lateral branches of much- 
branched filaments, which pro- 
ject from the wall of the concep- 
tacle. They are oval cells which 
produce numerous sperms. A 
curious feature of Fucus is that 
the eggs as well as the sperms are 
discharged from the conceptacle 
before fertilization. The eggs 
while passively floating about 
are surrounded by swarms of 
sperms, which sometimes, by their 
vigorous movements, give the 
eggs a rotary motion. In fertil- 
ization one sperm, after pene- 
trating the cytoplasm of the egg, 
fuses with the egg nucleus and 
thus an oéspore is formed which —_F 6. 279. — A portion of a plant 
develans & naw plane of Sargassum vulgare, showing the 
CYEIOP P : floats and the stem- and leaf-like 
Gulfweeds (Sargassum).—  gtructures. X 2. 
The Gulfweeds, well known in 
connection with the Sargasso Sea, are sometimes a meter in 
length and are more differentiated than the Rockweeds (Fig. 
279). In form the stalks and leaf-like branches resemble very 
much the stems and leaves of the higher plants, although they 
are very different in structure. The stems are at first anchored 
by root-like holdfasts and bear many stalked air bladders, which 
buoy up the plant when attached and float it when torn free. 
Other short, thick, axillary branches contain the conceptacles. 
So far as known their reproduction is similar to that of the Rock- 
weeds. 
