350 Field, Forest, and Wayside Flowers 
Some weeds lay hold on the passer-by, quadru- 
ped or biped, and force him, will he, nill he, to sow 
their seeds abroad. To bring this result about, 
the seeds or fruits are barbed, and they claw the 
unwary traveller and cling to him with exasperating 
constancy. When the ‘‘stickers’’ are at last picked 
or rubbed off, they fall to the ground, probably 
many rods from the spot where they grew, and 
thus Nature’s purpose with regard to them is 
achieved. This is the way the ragweed travels. 
The thorny seed-vessels of the cockle-bur and the 
burdock also obtain free transportation in return 
for their close attachment to some wayfarer, quad- 
ruped or biped. So successful have been these 
schemes that the weeds which put them into prac- 
tice have travelled half around the globe. Like an 
invading army they push further and further on, 
despite all the resistance of the owners of the soil. 
Many, indeed most, of the dooryard weeds come 
from the Old World, and have already travelled 
across this continent to the newly-cultivated lands 
of the far West. Some varieties seem unable to 
live far from human habitations, and persistently 
follow us up in the teeth of all opposition. Like 
the medieval Highlanders they have become sturdy 
and resourceful in the stern training-school of con- 
