16 
SEED DISPERSAL, 
Fid. 9. — Branch of snap-willow root- 
ing at one end. 
Fig. 10. — Portion 
of a branch of 
the cottonwood 
as it fell from 
the tree. 
group of seven 
white willows, near 
a brook on the 
campus of the 
Michigan Agri- 
cultural College, 
was at one time 
loaded with sleet. 
There was consider- 
able snow on the 
ground, which, of 
course, was covered 
with an icy crust. 
In a little while the 
sleet melted from 
the fallen branches 
strewn about, and 
a moderate breeze 
then drifted the 
smallest of the 
twigs in consider- 
able numbers over 
the icy snow. Some 
of these were found 
thirty rods distant 
from the parent 
trees — not down 
stream in the valley 
s 
