424 VEGETABLE PHYSIOLOGY 
in which they are developed are termed antheridia and 
oogonia respectively. 
In the group of Fungi similar differentiation of gametes 
oceurs, but motile antherozoids are very rare, confined 
indeed to the genus Monoblepharis. In other cases they 
are generally undifferentiated masses of protoplasm which 
do not escape from their antheridia, but are conducted 
directly from it into the female organ, where the process 
of fusion takes place. In Pythium the oogonium is a 
swelling at the end of a hypha, which is cut off from the 
rest by a transverse wall. Its contents divide up into an 
oosphere and a certain amount of protoplasm, which sur- 
rounds the latter. The antheridium is another hyphal 
branch, which becomes closely pressed to the oogonium. 
A tube is put out by the antheridium, which perforates the 
wall of the oogonium, and the male cell, which is formed 
in the same way as the female one, 
’ passes over into the female organ and 
fuses with the oosphere. 
In some other Fungi a similar 
arrangement of the organs is brought 
about, but the male cell does not pass 
over into the oogonium. 
A curious variation is seen in the 
red seaweeds, the Rhodophycee. The 
female organ, known as a procarpiwm, 
does not produce any differentiated 
oosphere, but the contents of the 
male cell pass by means of an elon- 
gated structure called a trichogyne 
(fig. 172) into its interior and appa- 
He, eee gocanrrum or rently fuse with the whole of its 
tv, trichogyne. protoplasm. The male cell in these 
plants is not naked as in other 
cases, but has a cell-wall. A somewhat similar condition 
is met with among the Ascomycetes, though whether 
fusion of the contents of the cells takes place is disputed, 
