INTRODUCTION 



13' 



pokeweed, plum, etc.) ; or, third, by burying them for 

 later use as food and then failing to dig them up. Squir- 

 rels are perhaps most active in this way : they bury im- 

 mense numbers of nuts and acorns. 



Man in his various activities is the greatest of all seed 

 distributors. Consciously and purposely he collects seed 

 in all parts of the world and transports it to places where 



FIG. 10— PRICKING OUT SEEDLINGS IN FLAT 

 Note the "spotting" board for spacing the plants evenly, 



it is to be planted; unconsciously he carries weed seeds 

 in bedding and packing, on ships and trains. He may 

 accidentally or purposely mix such seeds with valuable 

 ones and thus introduce them where the shipments are 

 distributed. The progress of the race westward from 

 India, Assyria, Palestine, Egypt, the Mediterranean and 

 Northern Europe to America and Australasia may thus be 

 traced by weeds and cultivated plants carried by man. 



26. Seed transportation is conducted upon an extensive 

 scale by scores of wholesale and retail seed merchants in 



