236 ESS A YS. 



Xanthium, Ambrosia artemisicefolia, Verbena hastata, V. 

 iirticifolia, etc., Veronica peregrina, Solanurn Carolinense, 

 various species of Amarantus and Euphorbia, Panicum capil- 

 lare, etc. Of late, and in consequence of increased commu- 

 nication with the Mississippi region and beyond — especially 

 by railroads — other plants are coming into the eastern 

 States as weeds, step by step, by somewhat rapid strides ; 

 such as Dysodia chrysanthemoides, Matricaria discoidea, 

 and Artemisia biennis. Fifty years ago Rudbeck'ia hirta, 

 which flourished from the Alleghanies westward, was unknown 

 farther east. Now since twenty years, it is an abundant and 

 conspicuous weed in grass-fields throughout the eastern States, 

 having been accidentally desimated with Red Clover seed 

 from the western States. 



There are also native American weeds, doubtless indigenous 

 to the region, such as Asclepias Cornuti, Antennaria mar- 

 garitacea, and A. plantaginifolia, and in enriched soils Phy- 

 tolacca decandra, which have apparently become strongly ag- 

 gressive under changed conditions. These are some of the 

 instances which may show that predominance is not in conse- 

 quence of change of country and introduction to new soil. 



In many cases it is easy to explain why a plant, once intro- 

 duced, should take a strong and persistent hold and spread 

 rapidly. In others we discern nothing in the plant itself 

 which should give it advantage. Lespedeza striata is a small 

 and insignificant annual, with no obvious provision for dis- 

 semination. It is a native of China and Japan. In some un- 

 explained way it reached Alabama and Georgia, and was first 

 noticed about thirty-five years ago ; it has spread rapidly 

 since, especially over old fields and along roadsides, and it is 

 now very abundant up to Virginia and Tennessee, throughout 

 the middle and upper districts, reaching even to the summits 

 of the mountains of moderate elevation. In the absence of 

 better food it is greedily eaten by cattle and sheep. The 

 voiding by them of undigested seeds must be the means of 

 dissemination ; but one cannot well understand why it should 

 spread so widely and rapidly, and take such complete posses- 

 sion of the ground. It is one of the few weeds which are 

 accounted a blessing. 



