260 
PLANT STUDIES 
tinguish them from the ciliated sperms, or spermatozoids, 
which have the power of locomotion, these motionless male 
gametes of the Eed Algae are usually called spermatia 
(singular, spermatium) (Fig. 228, A, s). 
The oogonium is very pe- 
culiar, being differentiated 
into two regions, a bulbous 
base and a hair-like process 
(trichogyne), the whole struc- 
ture resembling a flask with a 
long, narrow neck, excepting 
that it is closed (Fig. 228, A, 
o, t). Within the bulbous part 
the egg, or its equivalent, is 
organized ; a spermatium at- 
taches itself to the trichogyne 
(Fig. 228, A,s)', at the point of 
contact the two walls become 
perforated, and the contents 
of the spermatium thus enter 
the trichogyne, and so reach 
the bulbous base of the oogo- 
nium. The above account 
represents the very simplest 
conditions of the process of 
fertilization in this group, and 
gives no idea of the great and 
puzzling complexity exhibited 
by the majority of forms. 
After fertilization the trich- 
ogyne wilts, and the bulbous 
base in one way or another de- 
velops a conspicuous structure 
called the cystocarp (Figs. 228, 229), which is a case con- 
taining asexual spores ; in other words, a spore case, or kind 
of sporangium. In the life history of a red alga, there- 
~A 
FIG. 229. A branch of Polysiphonia, 
one of the red algae, showing the 
rows of cells composing the body 
(A), small branches or hairs (B), 
and a cystocarp (C) with escaping 
spores (D) which have no cilia (car- 
pospores). CALDWELL. 
