68 GENUS ARTEMISIA. 



RELATIONSHIPS. 



The large, heterogamous heads with numerous flowers, the fertile achenes in both ray 

 and disk, and the absence of specialized features indicate that this is one of the most 

 primitive of Artemisias. It occurs native in eastern Siberia and is apparently not far 

 removed phylogenetically from A. vulgaris, some large-headed forms of which occupy 

 the same phytogeographic area. The American species which it most closely resembles 

 is A. franserioides of the southern Rocky Mountains, and since this species has no close 

 relatives in America it seems not impossible that it is an offshoot from the stelleriana 

 stock. The agreement between the two in essential characters and somewhat in the cut 

 of the leaf is quite close, although the dissection has been carried much farther in fran- 

 serioides and the individual flowers are reduced in size. A. stelleriana appears to be a 

 non-plastic species, since no varieties or forms have been described, as far as we have 

 been able to learn. 



ECOLOGY AND USES. 



Artemisia stelleriana is a perennial herb with creeping rootstocks, which forms consocies 

 on sandy shores and on dunes, often covering extensive areas as a pure community. 

 It has generally been assumed to be an escape from cultivation, in all its European and 

 American stations (Fernald, Rhodora 2:38, 1900), but it is a puzzling fact that it has 

 always escaped into the sands of seashores and lake-shores, and apparently never into 

 roadsides and waste places. 



The remarkably white herbage gives to this species a certain value as an ornamental 

 plant. It is therefore grown to a limited extent both in American and European gardens, 

 more especially for borders. Beyond this it is of no economic value. 



9. ARTEMISIA ALASKANA Rydberg, N. Am. Fl. 34:281, 1916. Plate 5. 



A perennial herb or perhaps shrubby at base, the lower portions not present on the 

 single specimen thus far collected, 4 dm. or more high, the odor not known; stems appar- 

 ently crowded at the base to form a tussock or close clump, mostly erect, simple except 

 below and in the inflorescence, striate, sparingly tomentulose; lower leaves crowded, 

 petioled, 3 to 5 cm. long, 1.5 to 4 cm. wide across the lobes, twice dissected, first pinnate 

 into 3 to 5 divisions, each of which is irregularly again cleft, or some leaves twice ternate, 

 the ultimate segments oblong or linear, obtuse, 0.4 to 2 cm. long, 2 mm. or less wide, 

 the whole leaf appressed silvery-tomentose on both sides; upper leaves 5 to 6 cm. long, 

 mostly with 1 or 2 linear lateral lobes and a 3-cleft terminal one, or simply ternate, the 

 lobes linear and obtuse, silvery-tomentose like the lower, the leaves of the inflorescence 

 ternately cleft to entire and scarcely reduced in length ; inflorescence a very open raceme, 

 or subpaniculate below, leafy throughout, 25 to 30 cm. long, 4 to 6 cm. broad; heads 

 heterogamous, on peduncles 1 to 7 cm. long, erect or nodding; involucre hemispheric, 

 4.5 to 5 mm. high, 6 to 7 mm. broad; bracts about 15 to 20 in addition to a few linear 

 subtending bracts of the peduncle, elliptic or ovate, obtuse, with broad scarious erose 

 margins, villous-tomentose; ray-flowers 7 to 16, fertile, corolla tubular, 1.5 to 2 mm. 

 long; disk-flowers about 50 to 60, fertile, corolla funnelform, 5-toothed, 2 to 2.5 mm. long, 

 glandular-granuliferous below; style of ray-flowers linear, obtuse, of disk-flowers flat, 

 strongly recurved, penicillate at the truncate apex; achenes nearly prismatic, truncate 

 at summit, faintly angled, glabrous. 



Known only from the type collection, between Nulata and Nowikakat, on the Yukon 

 River, west-central Alaska, July 23 to 27, 1889, Russell (US). 



RELATIONSHIPS. 



The close relationship between this form and the Siberian A. iurczaninoviana Besser 

 was suggested by Rydberg in connection with his original diagnosis. The similarity 



