CERTAIN ASCLEPIADS. 229 



Certain Asclepiads. 



Time was, and not very long since, when in all our books 

 the commonest milkweed, or silkweed of our northern States 

 and Canada bore the Latin designation, Asclepias Cornuti. It 

 passes by that name in works as recent as Gray's Synoptical 

 Flora (1878) and even in the sixth edition of his Manual (1890). 

 Only in the course of the very last years of the nineteenth 

 century, and under the influence of new ideas as to the invio- 

 lability of the principle of absolute Linnaean priority, was 

 the old but very erroneous and misleading name A. Syriaca 

 restored ; the name given it by Linnaeus, who himself never 

 had the remotest suspicion that his plant was at all American, 

 not to say exclusively such, and never seen in Syria at all. 



As early as 1844, and while as yet the best botanists held 

 that falsehood must not be propagated in the name of science 

 by even so much as a falsifying adjective plant name. The 

 principle is rational and sound. There are amateur botanists, 

 collectors of specimens, and makers of herbaria, both in this 

 country and in Europe, where now our plant has long since 

 become naturalized, who have never supposed for a moment 

 that the species is not a native of Asia, introduced here. The 

 name itself tells that lie to all such people ; and every one of 

 these may justly charge us with disseminating untruth, and 

 what we know to be an untruth, by using that as the legiti- 

 mate name of this common milkweed. 



But now, what is of quite special interest in this connection 

 is, that even Decaisne's name for the species, the name T. 

 Cornuti, is false as well as the other, though in a different way ; 

 for any one possessing a botanist's trained eye, accustomed to, 

 and at all familiar with our milkweeds, opening at page 90 of 

 Cornut's volume, discovers even at first glance that what is 

 there figured, so far from being the A. Syriaca of Linnaeus, is 

 really the A. obtusifolia of Michaux. The solitary, strictly 

 terminal, pedunculate umbel with its few-flowered laxity, as 

 ^Iso the small foliage, dispute its identity with the more com- 



Leaflets, Vol. II, pp. 229-260. 22 October, 1912. 



