178 PHILOSOPHICAL TRANSACTIONS. [anNO 1757. 



which supports the lobe leaves, is quite smooth in the poison-ash, as is also the 

 under side of the leaves ; whereas Dr. Koempfer, in his description of the mid- 

 rib of the true varnish-tree, calls it laeviter lanuginoso ; and in his description 

 of the lobes or pinnae he says, they are basi inequaliter rotunda ; whereas those 

 ,of the poison-ash come to a point at their footstalks nearly equal to that at the 

 top. These characters, Mr. Ellis thinks, are sufficient to prove that they are 

 different plants : and he blames Dr. Dillenius for having omitted these neces- 

 sary characters in his description of it ; and supposes this must have misled the 

 accurate Linneus, who quotes his Synonyma. But as Dr. Linneus is possessed 

 of Kcempfer's book, he would little have deserved the appellation of accurate in 

 this particular, had he not consulted the original, but trusted to a copy. But 

 this I know he has done, and is as well assured that the plants in question are 

 the same, as Mr. Ellis can be of the contrary. But here I must observe, that 

 the branch, from which Dr. Kcempfer's figure is taken, is produced from the 

 lower part of a stem, which seems to have been cut down, and not from a 

 flowering branch ; and it is not improbable that his description may have been 

 taken from the same branch : and if this be the case, it is easy to account for 

 the minute differences mentioned by Mr. Ellis ; for it would not be difficult to 

 produce instances of hundreds of different trees and shrubs, whose lower and 

 upper branches differ much more in the particulars mentioned by Mr. Ellis, than 

 the figure and description given by Koempfer do from the American toxicoden- 

 dron. I will only mention 2 of the most obvious : the first is the white poplar, 

 whose shoots from the lower part of the stem, and the suckers from the root, 

 are garnished with leaves very different in form and size from those on the up- 

 per branches, and are covered on both sides in the spring with a woolly down. 

 The next is the willow with smooth leaves, which, if a standard, and the head 

 lopped off, as is usual, the young shoots are garnished with leaves much broader, 

 and of different forms from those on the older branches ; and these have fre- 

 quently a hairy down on their under surface, which does not appear on those 

 of the older. So that a person, unacquainted with these differences in the 

 same tree, would suppose they were different. And the American toxicoden- 

 dron has varied in these particulars much more, in different seasons, than what 

 Mr. Ellis has mentioned. 



Mr. Ellis next says, that the toxicodendron mentioned by Mr. Catesby, in 

 his Natural History of Carolina, is not the same with that which is now called 

 by the gardeners posion-ash : but I am very positive of the contrary ; for most 

 of the plants in the nursery gardens about London were first raised from the 

 seeds which were sent by Mr. Catesby from Carolina ; part of which were sent 

 to the late Dr. Sherard, as is mentioned by him in the Philosophical Transac- 

 tions, N° 367 ; and another part came into my hands, from which I raised a 



