PESTIFEROUS PLANTS. 227 



The crop-grower necessarily introduces the condition of a bare 

 soil for a portion of the year for every crop, and must therefore 

 accept the situation : while he invites their presence and develop- 

 ment, even stimulating them in various ways by making the con- 

 ditions favorable for the growth of his crop plant, he must become 

 a competitor with the weeds for the possession of the soil. The 

 weed seeds are either in the soil or soon find an abundant en- 

 trance, and if the way is clear the young pests are up and doing 

 as with the morning sun. 



Most of our weeds, like much of our vermin, have come to us 

 from beyond the sea. Just how they emigrate in every case will 

 never be known ; some came as legitimate freight, but many were 

 " stowaways." Some entered from border lands upon the wings 

 of the wind, on river bosoms, in the stomachs of migrating birds, 

 clinging to hairs of passing animals, and a hundred other ways 

 besides by man himself. Into the New England soil and that 

 south along the Atlantic seaboard the weed seeds first took root. 

 Also the native plants, with a strong weedy nature, developed 

 into pests of the farm and garden. Many of the native weeds 

 are shy and harmless in comparison with the persistent and 

 pugnacious ones that have like vagabonds emigrated to our 

 shores. Why should it be that plants of another country not 

 only find their way here, but after arriving assert themselves 

 with a vigor far surpassing our native herbs ? Dr. Gray, in writ- 

 ing upon this point, says, "As the district here in which the 

 weeds of the Old World prevail was naturally forest-clad, there 

 were few of its native herbs which, if they could bear the expos- 

 ure at all, were capable of competition in the cleared land with 

 emigrants from the Old World." The European weeds had 

 through long ages adapted themselves to the change from forest 

 to cleared land, and were therefore prepared to flourish here in 

 the rich forest soil that was suddenly exposed to the sun and sub- 

 jected to other new conditions by the felling of the trees. To go 

 back of this we are not sure that the ancestors of some of our 

 European weeds ever came from the forests, but instead were 

 brought into the cleared-up lands from open regions in the early 

 days of agriculture in the Old World. As civilized man moved 

 westward, the weeds followed him, re-enforced by new native ones 

 that soon vied with those of foreign blood. Not satisfied with 

 this, these natives of the interior ran back upon the trail and be- 

 came new enemies to the older parts of our land. The conditions 

 favorable for the spreading of weeds have increased with the 

 development of our country, until now we are literally overrun. 

 Weeds usually as seeds, go and come in all directions, no less as 

 tramps catching a ride upon each passing freight train than in 

 cherished bouquets gathered between stations and tenderly cared 



