A. SENJAVINENSIS. 65 



being most noticeable in glomerala. But the meager material at hand scarcely justifies 

 the taxonomic use of this feature at present. The probable explanation as to the 

 phylogeny of the last three subspecies is that each represents a distinct evolutionary line 

 which has become fixed through isolation. 



ECOLOGY AND USES. 



Artemisia norvegica is a perennial herb with caudex or short rootstock, which blooms 

 from early July to October. It forms clans in alpine and Arctic meadows and subalpine 

 forests, and sometimes becomes a consocies on stony slopes or in burned areas. It 

 usually indicates moist areas in forests, where it is often associated with Carex, Juncus, 

 Erigeron, Mimulus, etc. No uses are known for this species. 



6. ARTEMISIA SENJAVINENSIS Besser, Nouv. Mem. Soc. Mosc. 3:65, 1834. 



Plate 4. 



A perennial herb with a thick multicipital caudex, about 0.5 to 1 dm. high, the odor 

 not known; stems numerous, forming dense tufts, simple above the basal branches, the 

 central ones erect, the outer ones spreading, densely villous with long shaggy white or 

 tawny hairs; basal leaves densely crowded, sessile, less than 1.5 cm. long, simply 3- to 

 5-cleft into ovate, acute lobes, very densely silky-villous like the stems, the hairs longer 

 than the lobes and nearly concealing the leaf; upper leaves 1 to 2 cm. long, cleft less than 

 halfway into elliptic rather obtuse lobes, similarly silky-hirsute; inflorescence a congested 

 globoid terminal spike, 1 to 2 cm. long and of equal breadth; heads heterogamous, sessile, 

 erect; involucre campanulate, about 4 mm. high and 4 to 5 mm. broad; bracts about 8, 

 elliptic, denticulate, obtuse, with brown scarious margins, densely long-villous; ray- 

 flowers 5 to 8, fertile, corolla tubular, about 2 to 2.4 mm. long, lobed, granular; disk- 

 flowers 10 to 20, fertile, corolla funnelform, about 2.5 to 3 mm. long, 5-toothed, granular; 

 style-branches of ray-flowers ligulate, truncate, entire, of disk-flowers dilated, rounded 

 and erose at summit; achenes nearly cylindric, with about 5 vertical ribs or nerves, 

 glabrous. 



Western Alaska and eastern Siberia. Type locality, Senjavin Sound, Siberia. Collec- 

 tions: Kotzebue Sound, western Alaska, ' Beechey" (Gr, ex-herb. Hooker); same locality, 

 "Arn-ott" (NY); Arakamtchetchene Island, Bering Straits, 1853-56, Wright (NY, US). 

 Siberian collections as far as known include only the following: Type collection, Mertens 

 (Gr, ex-herb. Acad. Petrop.); Fretum Senjavin, Bongard (NY, other species also have 

 been distributed with these data) ; Terra Tschuktschorum, St. Lawrence Bay, Eschscholtz 

 (according to Ledebour, Fl. Ross. 2:589, 1844-46). 



SYNONYMS. 



1. Artemisia and rosacea Seeman, Botany Voy. Herald 34, 1852.— The excellent plate accompanying 

 the original description leaves no doubt that this is exactly A. senjavinensis. Type locality, Kotzebue Sound, 

 Alaska. 



2. A. SEMAVi.NTENSis Besser, Nouv. Mem. Soc. Mosc. 3:65, 1834. — The original spelling of the specific name; 

 corrected to senjavinensis by IJesser (Bull. Soc. Nat. Mosc. 9:64, 1836). 



RELATIONSHIPS. 



There is considerable evidence to support the view that this is a reduced far-northern 

 derivative either of A. macrobotrys or A. norvegica. The small size of the heads might 

 seem to indicate the former, but the very dense and persistent pubescence is more like 

 that of certain forms of the latter, which also includes a small-headed subspecies glom- 

 erata. Both senjavinensis and glomerata exhibit an extreme reduction in habit, as a 

 result of the arctic conditions under which they grow, so that they are closely similar in 

 aspect, but they are not sufficientlj^ close in other features to justify their inclusion in 

 one collective species. The former is unique in the extreme development of the long and 

 dense villous pubescence, and is especially distinct from glomerata in the cut of the leaf, 



