108 A TEXT-BOOK OF BOTANY 
(3) Sexual reproduction is indicated by 
oN, 88 4 | ON 
P| o—P | nay oe paaye —P, 
indicating that two special cells (gametes) are produced by 
the plant, that these two fuse to form one (odspore), which 
then produces a new plant. 
66. Cladophora.—This plant is found attached to 
sticks and stones at the edge of ponds or lakes, and is often 
@ so abundant as to form thick 
mats of long anchored filaments. 
It is easily distinguished from 
Ulothriz, for it is a much coarser 
plant and branches freely (Fig. 
98). It is mentioned here both 
because it is common and _ be- 
cause it illustrates a branching 
filamentous body. Just as in 
Ulothrix, reproduction in Clado- 
phora is carried on by means of 
swimming spores, and also by 
the fusion of swimming gametes 
to form odspores. 
wy 67. CEdogonium.— The fila- 
Fic. 98. 0h Hoailesas a branch: Ments of Gdogonium are long 
ing filament, each of whose and simple, the lowest cell act- 
cells contains several nuclei. 
ing as a holdfast, as in Ulothriz 
and Cladophora. In each cell a nucleus may be seen (Fig. 
99), and apparently several chloroplasts; but really there 
is only one large complex chloroplast. 
Any one of these cells may produce within itself a single 
large swimming spore, which escapes from the mother-cell 
into the water (Fig. 99, C). At its more pointed clear end 
there is a little crown of cilia, by means of which it swims 
about rapidly. These spores finally anchor themselves, 
and each one produces a new filament (Fig. 99, D and E£), 
