568 Hitt: NOTES ON MIGRATORY PLANTS 
bunch of which grew by the side of nearly every farmhouse, 
should have become so troublesome. I have since seen it flourish- 
ing by waysides in localities where it was then known chiefly as a 
flower, but nowhere in such abundance as it shows here. Acres 
of the weed can be seen in the waste ground along the drainage 
canal and railroads running parallel with it, as well as on the de- 
bris of the numerous quarries of limestone. City lots whose soil 
is in any way disturbed are apt to be stocked with it. As it can 
attain a height of six or seven feet—three or four feet being a com- 
mon height, and branching freely—it soon overshadows the more 
humble plants and becomes the one in possession almost exclu- 
sively. In richer soil, especially of bottom lands, its most impor- 
tant competitor is the great ragweed, Ambrosia trifida, which 
grows higher and is apt to supplant it. Being often xerophytic in 
habit it frequents dry localities, such as hard clay hills and banks, 
rubbish-heaps of limestone chips and intermingled dirt from quar- 
ries. It is a common weed between the grassy border of a high- 
way and the well-beaten track, where the ground is sufficiently 
disturbed to permit its seeds to germinate but not enough used to 
destroy the plants. It readily takes root on a hilly slope or bank 
on which the rains cut out gullies, washing away the soil so as t0 
prevent less hardy plants gaining a foothold. Here in a sense it 
may serve a useful purpose in holding the soil or preparing for 
other growth. 
AMARANTUs BLITOIDES Watson. This is one of our most Pel 
sistent weeds. As nearly as I can learn it appeared in the vicin- 
ity of Chicago early in the seventies. I saw it first in 1875, after 
it had become well established, but not covering any great area. 
Since that time it has spread extensively and become common, 
particularly along waysides and railways. It bears a great deal 
of trampling, and grows where it is subject to very hard usage 
much like the knotgrass, Polygonum aviculare. Being prostrate, 
it cannot be mown down like the white melilot, but must be 
pulled or dug up. It is now the most common of our amaranths 
except in cultivated ground, where the tumble-weed, A. 8” aecl- 
ans, is better adapted to the abrupt and frequent disturbances of 
soil due to cultivation, The prostrate plant cannot take advantage 
of the wind for dissemination. It is often quite troublesome ' 
