82 
SEED DISPERSAL. 
what was being sold on the market as seed of red clover ; 
this specimen contained 40 per cent of seeds of rib-grass 
or narrow-leaved plantain. 
Man introduces some seeds of weeds with unground 
feed stuff. He introduces some with barnyard manure 
drawn from town. He gets some 
in the packing of nursery stock, 
crockery, baled hay and straw. 
For example, in 1895, baled hay 
from Kansas or that vicinity ex- 
amined at the Missouri Agricultural 
College was found to contain fifteen 
species of weeds. Others from the 
west were examined in Michigan 
and found to contain much foul 
stuff. Some are carried from farm 
to farm by wagons, sleighs, or 
threshing machines ; or they are spread by plows, culti- 
vators, and harrows. A few are introduced to grow for 
ornament or food, and afterwards spread as weeds. A 
number have been shipped to distant lands in the earth 
of ballast, which is often unloaded and reloaded at wharves 
where freight is changed. They are carried along the 
highway, strung along the towpath of canals, or are 
carried in the trucks or in the cars of railroads. They 
are imported and exported around the world in fleeces of 
wool. They float down irrigating ditches from farm to 
farm, and with the water are well distributed. 
Fig. 65. — Two seeds of narrow- 
leaved plantain sucli as are be- 
coming common in clover seed. 
The lower one and the one at 
the left are seeds of red clover. 
