Minnesota Plant Life. 19 



son why throughout Minnesota the lake-shore vegetation is so 

 homogeneous. Every bay is visited at some time during the 

 year by wild fowl and in the mud on their feet they carry about 

 the seeds of a variety of plants. It is therefore, those water- 

 edge plants which have seeds not too large to be thus trans- 

 ported that are the more widely distributed. Especially if the 

 seed is of a kind attractive to the bird is it likely to be removed. 

 Thus ducks, though they eat hundreds of thousands of young 

 wild-rice plants encased in their seed-coats, nevertheless from 

 their very habit of using these plants for food distribute them 

 more widely than if they were not thus agreeable to their taste. 



Migrating animals, like the bison which once roamed in enor- 

 mous herds over the whole prairie region, must have picked up 

 in their fur, as they wallowed in the sand or on the banks of 

 streams, countless seeds of a great variety of plants and carried 

 them to all parts of their range. In this way, plants having 

 seeds provided with attachment-prongs, like the tick-trefoils, 

 beggars'-lice, burdocks and cockleburrs must have obtained 

 through the agency of animals far greater opportunities for 

 travel than were enjoyed by species the seeds or fruits of which 

 were hard and smooth. 



The fancy of animals and birds for certain sleeping places 

 has also influenced plant distribution, and their habits of wan- 

 dering in the woods and by the water have been utilized by cer- 

 tain kinds of plants, and some remarkable adaptations exist, 

 such as the curious explosive seed-pods of the touch-me-not. 

 This common plant, when brushed against, explodes its fruits, 

 throwing out the seeds where they may be caught in the fur of 

 a passing animal and carried away. Certain exotic gourd-plants 

 too, have explosive fruits which when agitated by a slight 

 touch shoot out the seeds and these, provided with a viscid 

 membrane, readily adhere to the passing bird or animal. Other 

 plants have their seeds enclosed in edible areas, as for example 

 the gooseberries, currants, apples, peaches, raspberries, junipers 

 and a host of others. In such fruits the seeds are themselves 

 protected by hard coats which resist the digestive processes of 

 the animal or bird and they can thus pass through its body with- 

 out injury. Sometimes the instincts of animals benefit the 

 plant, as when a squirrel carries off an acorn and buries it from 



