A. FRIGIDA. 



109 



6212 (Gr, NY); Flagstaff, Arizona, September 5, 1894, Tourney (UC); Table Mountains, 

 Nevada, Purpus 63S2 (UC) ; eastern Washington, Griffiths and Cotton 362 (NY) ; Thomp- 

 son Falls, Idaho, Sandberg 981 (Gr, NY) ; vicinity of Banff, Alberta, McCalla 2019 (NY, 

 US); Fort Chippewyan, Athabasca, Preble 187 (US); Kamloops, British Columbia, 

 July 28, 1890, Macoun (US); Klondike Valley, near Dawson, Yukon, Macoun 79016 (NY). 

 MINOR VARIATIONS AND SYNONYMS. 



1. A. FRIGID.^ GMELINIANA BessGf, HookoF, Fl. BoF. Am. 1:321, 1833. — Only a foliage form of A. frigida. 

 Lower leaves long-petioled, 3-parted, the segments 5-parted, lobes linear, acute, the middle ones short, lowest 

 lobes stipule-like; cauline leaves pinnatisected, the lower segments remote from the upper. Collected on the 

 Saskatchewan. 



2. A. viRG.iTA Richardson, Franklin's Journey, App. 747, 1823. — According to W. J. Hooker (Fl. Bor. Am. 

 1:321, 1833), this is identical with No. 1 of this list. 



RELATIONSHIPS. 



Artemisia frigida is most nearly approached by species of northern Europe and Siberia. 

 Since it is most plentiful and variable in northern regions, it seems quite certainly to be 

 of boreal origin. It is in no way connected with Mexican or other southern forms. 

 Several Old World species of its section resemble it in general appearance, but differ in 

 such details as having pilose or even lanate corollas. This leaves but one species to 

 which it can be directly compared, namely, A. rupestris Linnaeus, a rather common plant 

 from Scandinavia to Siberia, where it overlaps the range oi frigida. These two approach 

 each other so closely in habit as well as in all important characters that they might almost 

 be taken as one collective species. A. rupestris is apparently the derivative, since in it 



Table 8. — Variation in Artemisia frigida (a stable species). 



the inflorescence has undergone reduction to a nearly or quite simple raceme, as in .4. 

 scopulorum, and the leaves have a more decidedly pinnate arrangement of the segments. 

 The foliage is almost glabrous and therefore green instead of silvery-white as in A. 

 frigida. It apparently has larger heads with more numerous flowers, about 70 in the 

 specimens at hand, but this may not be constant. While these characters prevent the 

 merging of A. frigida into this older species, the phylogenetic connection between the 

 two is established with reasonable certainty. The nearest American representatives are 

 A. scopulorum and A. pattcrsoni. It seems probable that these have descended directly 

 from A. frigida, as shown under the next species. 



Variation within the species has resulted in the recognition in Asiatic collections of a 

 considerable number of forms, some of which have been treated as species. In America, 

 however, there is a remarkable constancy in all essential characters. The only form 

 indicated as in any way divergent is the one listed above under Minor variations. 



