450 Rvdberg : Rocky Mountain flora 



The other Nelsonian species have in my opinion no claim to 

 specific rank. Two duplicates of the type of Artemisia gracilenta 

 A. Nels., one in the Columbia University herbarium and the other 

 in the New York Botanical Garden collection, are almost identical 

 with the two original specimens of A . floccosa Rydb. The only dif- 

 ference is that the segments of the leaves of the former are somewhat 

 narrower. There are also two duplicates of A. paucicephala 

 A. Nels., which differs from A. floccosa only in the fact that the 

 upper leaves are entire. As Nelson himself unites A. pauci- 

 cephala and A. gracilenta and the original A. floccosa is intermed- 

 iate between the two, I see no reason why they should not be re- 

 duced to synonyms of A. floccosa, which is three years older. 



Artemisia subglabra A. Nels., of which there are two duplicates 

 here, is identical with A. graveolens Rydberg, three years older. 

 The leaves of even Nelson's own specimens show traces of tomen- 

 tum on the lower surface. The species is related to A. discolor, 

 not to A. saxicola, with which Nelson has placed it. 



Artemisia natronensis A. Nels. is, according to a duplicate of 

 the type and several specimens distributed from the University 

 of Wyoming, the same as A. longifolia Nutt., as that species is 

 understood. The specimens which I referred to A. natronensis 

 in my Flora of Colorado do not belong there. They are unusually 

 large-headed A. diver sifolia or at least closely related to it. I 

 wish to make this correction here. 



Now let us take up the species reduced by Professor Nelson. 

 Artemisia Sconleriana (Besser) Rydb. and A. Forwoodii S. Wats, 

 are reduced to synonyms of A. canadensis . 



Artemisia canadensis Michx. is a subarctic plant and not found 

 in the Rocky Mountains within the United States. The type 

 came from the shores of the Hudson Bay. It is a low plant with 

 the leaves mostly basal, with narrowly linear divisions, and com- 

 paratively few heads nearly as large as those of A. spitJiamaea 

 Pursh {A. borealis Auct. Am.) and in a narrow panicle. I have seen 

 specimens from the White Mountains; Vermont; the Gaspe 

 Peninsula, Que.; Keweenaw Point, Mich.; and the Yukon Ter- 

 ritory; but from nowhere in our western states. The specimens 

 named Artemisia canadensis from there belong to A. Forwoodii 

 or A. Sconleriana. Whether the latter two should be regarded as 



