KEPRODUCTIVE ORGANS 
113 
75. Dispersal by locomotion. The common method of 
locomotion is by means of movable hairs (cilia) developed 
upon the reproductive body, which propel it through the 
water (see Fig. 109). 
Swimming spores are 
very common among 
the algae, and at least 
one of the gametes 
in algae, moss-plants, 
and fern-plants has 
the power of swim- 
ming by means of 
cilia. 
76. Dispersal by 
water. It is very 
common for repro- 
ductive bodies to be 
transported by cur- 
rents of water. The 
spores of many water 
plants of all groups, 
not constructed for 
locomotion, are thus 
floated about. This 
method of transfer is 
also very common -, 
among seeds. Many 
seeds are buoyant, or 
become so after soak- 
ing in water, and 
may be carried to 
great distances by 
currents. For this reason the plants growing upon the 
banks or flood-plains of streams may have come from a 
wide area. Many seeds can even endure prolonged soak- 
ing in sea-water, and then germinate. Darwin estimated 
FIG. 112. The upper figure to the left is ar opening 
pod of fireweed discharging its plumed seeds. 
The lower figure represents the seed-like fruits 
of Clematis with their long tail-like plumes. 
After KERNER. 
