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supposed sterility, therefore, should seem to result chiefly from the peculiarity 
of their situation and constitutions, and not from any real defect in the 
formation of all, or any of their parts of fructification, as has sometimes been 
ingeniously conjectured by some botanists. 
The pubescent Poison-oak (Rhus Toxicodendron), like its congener the 
smooth-rooting Poison-oak (Rhus radicans), trails along the ground, and 
has, like that shrub, the property of sending down radicles into the earth, 
by which the plant admits of great increase, in any of the summer months. 
In such situations, however, I have not seen it produce seeds so readily 
as in drier and more pinching places, where it loses, in a great degree, its 
radicating principle, grows more stiff and robust, and produces annual crops 
of pale yellow striated berries. There is a remarkable instance of this 
kind now existing in a wall, belonging to the Physic Garden of the 
company of Apothecaries at Chelsea, out of a chink in the side of which, 
and near the ground, grows a strong plant of this Rhus, that has prospered 
there ever since the time of the celebrated Miller, and which Mr. Fair bairn, 
the company’s present gardener, obligingly assured me was what Miller 
called the second Toxicodendron, in his Gardener’s Dictionary; it is, in all 
probability, the identical plant from which the description in that well-known 
work was made; it seeds annually, but none of its lower shoots exhibit the 
least radicating propensity, although other plants of the same kind, in the 
shady parts of the same garden, have that quality in great perfection, but I 
believe they rarely produce seeds; so much do local circumstances affect and 
alter the most permanent and distinguishing characters of vegetables. 
I believe it is pretty generally known to gardeners, and others concerned 
in the pleasant and instructive employment of horticulture, says Dr. Alderson, 
that many other fibrous plants, which, like the Rhus Toxicodendron, possess the 
power of increasing themselves in any considerable degree by their roots, have 
that property materially lessened when the place they grow in happens to be 
dry and poor, for Nature has chiefly allotted them rich and moist habitations, 
and with her usual care, constructed their constitutions accordingly; the 
alteration such plants undergo, in such a soil, is doubtless in the direction of 
their juices, which (being fewer) appear to pass by the lower and less noble 
parts (they had before rendered luxuriantly radicant or prolific), and mount 
upwards by a natural and almost instinctive impulse, to feed and mature, 
with collected force, the infant germens (seed-vessels) which they had before 
too sparingly supplied with nourishment. 
