28 
SEED DISPERSAL. 
Fig. 23. — Seed of milkweed 
with, a corky margin en- 
abling it to float ; a seed 
were especially fitted for sailing through the air, aided 
by their numerous long, silky hairs. These hairs are no 
hindrance to moving by water. I discovered one little 
thing in reference to the seed which makes me think the 
Designer intended it should to some 
extent he carried by water. The flat 
seed has a margin, or hem, which 
must be an aid to the wind in driving 
it about ; but this margin is thickened 
somewhat by a spongy material. 
With the margin it floats, without 
it the seed sinks in fresh water. A 
with such margin removed f ew cranberries were found in the drift- 
sinks at once. 
wood. These contain considerable air 
in the middle, near where the seeds are placed, 
as though the air was intended to support 
them on top of water. 
These berries are colored and edible — 
qualities that attract the birds. And here 
we find in several places the bulblets of a 
wild garlic, Allium Canadense, which grows 
on the river bottom. These bulblets are 
produced on top of the stem with the flowers, fig. 24. — Cran- 
and float on the water. The seeds of the 
white water lilies, and yellow ones also, by 
special arrangement float about on the water 
with the current or the wind. The coffee tree grows 
rather sparingly along some of the streams, and on moist 
berry contain- 
ing an air space 
which helps it 
to float. 
