236 ESSAYS. 
Xanthium, Ambrosia artemisiefolia, Verbena hastata, V. 
urticifolia, ete., Veronica peregrina, Solanum Carolinense, 
various species of Amarantus and Euphorbia, Panicum capil- 
lave, ete. 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 Rudbeckia 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 disseminated 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. 
