60 



GENUS AKTEMISIA. 



5d. Artemisia norvegica glomerata (Ledebour). — Stems 0.4 to 1.2 dm. high; 

 foliage gray with a dense silky-villous pubescence; lower leaves 0.8 to 2 cm. long, the 

 blade flabelliform or orbicular in outline and less than 1 cm. long, 2 or 3 times ternately 

 divided into linear acute divisions, the petiole slender; inflorescence a single dense terminal 

 globoid cluster of heads, 1 to 2 cm. across; heads small, the involucre 3.5 to 5 mm. high; 

 disk-flowers 16 or more, their corollas about 2.5 mm. long. (A. glomerata Ledebour, 

 Mem. Acad. St. Petersb. 5:564, 1815.) Western Alaska to eastern Siberia and the 

 Kurile Islands. Type locality, St. Lawrence Bay, Siberia. Collections: Cape Thompson, 

 Alaska, Muir 80 (Gr); Arakamtchetchene Island, Bering Straits, 1853-56, Wright (Gr); 

 St. Lawrence Bay, eastern Siberia, July 24, 1895, Sharp (Phila.); St. Lawrence Bay, 

 Eschscholtz (Gr, ex-herb. Ledebour). 



MINOR VARIATIONS AND SYNONYMS. 



1. A. ARCTICA Lessing, Linnaea 6:213, 1831. — The nearly glabrous form of A. norvegica saxatilis. Most 

 common in the far Northwest, but specimens which are almost entirely glabrous come from as far south as 

 the southern Sierra Nevada of California (Purpus 1635, UC), and all degrees of pubescence are found in dif- 

 ferent collections. It seems quite unlikely that the amount of pubescence is other than a response to ecologic 

 conditions. It is therefore not surprising to find that in the far Northwest the plants are mostly, although 

 not all, of the nearly glabrous type, and that in the arid Rocky Mountain districts they are strongly pubescent, 

 while in the Cascades and Sierra Nevada occur both sorts with numerous intermediate forms. A. arctica 

 also differs, according to Rydberg, in the inner bracts, which are said to be "ovate, obtuse, or rarely acutish, 

 with a broadly lanceolate green center," while those of true saxatilis {A. saxicola Rydberg) are said to be 

 "ovate, acute, with a narrowly lanceolate green center." There is, to be sure, some variation in the bracts, 

 but these run parallel neither with the variations in pubescence nor with geographic distribution, as is shown 

 by the series of 12 bracts represented in figure 5. Various forms referred to A. arctica by Besser, Gray, and 

 others belong partly to subspecies saxatilis and partly to subspecies heterophylla. The type locality of arctica 



-Inner bracts of Artemisia norvegica saxatilis: a to /, inner bracts from plants referable to true saxatilis because of 

 the strong pubescence on stems and foliage; a to I. inner bracts from plants referable to minor variation 1 

 (.4. arctica Lessing) because of the nearly glabrous stems and foliage, a, from Colorado (69460 UC); b, from 

 Colorado (489332 US); c. from Colorado (29773 UC); d, from California (91243 UC); e. from California (193585 

 UC); /, from California (63517 UC); g, from Alaska (204365 UC); h, from Alaska (204501 UC); i. from Alaska 

 (91242 UC);;, from California (29703 UC); t, from California (40555 UC);J,from California (91240 UC). All X 6. 



2. A. CHAMissoNiANA SAXATILIS Besser, in Hooker Fl. Bor. Am. 1:324, 1833. — .4. norvegica saxatilis. 

 ^3. A. COMATA Rydberg, N. Am. Fl. 34:263, 1916. — A form combining the greenish herbage and elongated 

 leaf-blades of A. norvegica saxatilis with the reduced stature (1. to 1.5 dm.) and narrow, racemo.se inflorescence 

 of heterophylla. Although the stems and foliage are nearly glabrous, the rachis of the inflorescence and the 

 peduncles are notably white-villous. The involucre is very dark and nearly glabrous. Type locality, Collinson 

 Point, Camden Bay, Alaska. (Illustration in Macoun and Holm, Rep. Canadian Arctic Exped. 5: plate 13. 

 figs. 3 and 6.) 



