RHUS. 131 



History. — This plant was first described by Cornutus {Plant. 

 Canad. Hist.), in 1635, but not brought into practical use 



* 



chiefly on the character of the leaves, yet Michaud, Pursh, Eaton, and later bota- 

 nists, who have had opportunities of carefully observing these plants, are of opinion 

 that they are mere varieties of the same species. The R. toxicodendron has been 

 described as a low self-supporting shrub, only two to three feet in height, with the 

 leaflets toothed or lobed at the margin, and pubescent ; while the R. radicans has 

 a stem from five to forty feet in height or rather in length (and even infinitely 

 longer than this), with the leaflets entire at their margins ; but the toothed leaflets 

 have been observed equally on the R. radicans as on -ft. toxicodendron, being 

 chiefly the radical leaves ; while the trailing character of the stem arises from the 

 locality in which it is found, Rhus radicans inhabits rocks and open places, while 

 the R. toxicodendron is generally found amidst higli forest trees. Professor 

 Eigelow states, " Among the plants which grow abundantly round Boston, I have 

 frequently observed individual shoots from the same stock having the character of 

 both varieties." It is also probable that the medicinal powers are increased or 

 lessened by the same cause, for it is natural to suppose that the virtues must be 

 more marked in those plants that are able to increase and thrive in power and 

 strength, than in those which are stunted and weakly. 



The following note is taken from the American edition of Jahr's Manual; — 

 <c Rhus radicans and Ehus toxicodendron are considered by some botanists as 

 varieties of the same species, but by a majority of them as distinct species. The 

 trunk of the radicans is from five to forty feet in height, and is furnished with an 



like 



it to adhere to trees and other objects, and be ths supported like a kind of vine. 

 The toxicodendron is a low, self-supporting shrub, only two or three feet in 

 height. When the radicans grows where it meets with no object suitable to its 

 support, its height is only four, five, or six feet, and its branches frequently recum- 

 bent. In a dry soil, the branches may not be recumbent, and the stunted radicans, 

 with few or no radicles, be mistaken for a toxicodendron, from which, however, it 

 is even then distinguished by the crookedness or obliquity of its trunk. As the 

 leaves of both plants are sometimes trifoliate, the toxicodendron always and the 

 radicans rarely on the same vine, though generally quinquefoliate, with leaflets 

 decidedly serrate, toothed, or lobed, and smooth and glabrous on both surfaces, as 

 well as smaller, terminal one the largest, the two next the footstalk the smallest 

 when fine , while* those of the toxicodendron are frequently entire at their margins, 

 and always sparingly toothed or lobed, and often on one side only, and these not 

 so fine as the preceding species, pubescent on both surfaces, but the inferior the 

 most so, and leaflets larger. Until the precise relation which the radicans and toxi- 

 codendron sustain to each other in their medical properties has been rigorously 

 determined, no specimens of then, should be collected, either for pathogenetic or 



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