58 GENUS ARTEMISIA. 



inflorescence, erect, striate, densely villous to glabrous, often reddish tinged; basal leaves 

 crowded, petioled, 1 to 15 cm. long including the petiole, 1 to 3 times pinnately divided 

 or parted into lanceolate or rarely linear or spatulate lobes, varying from silvery-silky 

 to glabrous; upper leaves less dissected; inflorescence normally an elongated terminal 

 panicle, 10 to 40 cm. long and 1 to 5 cm. broad but in some forms much reduced and 

 raceme-like, spike-like, or head-like ; heads heterogamous, peduncled or sessile, commonly 

 nodding; involucre hemispheric, 4 to 6 mm. high, 4 to 7 mm. broad (up to 8 mm. broad 

 in the original European form) ; bracts 9 to 20, broadly elliptic, obtuse, with greenish 

 medial portion and broad brown-scarious margins, villous to glabrous; ray-flowers 6 

 to 20, corolla narrowed upwards, 2 to 2.5 mm. long, obliquely toothed, villous or glabrous; 

 disk-flowers about 15 to 73, or even up to 120 in the typical form and in subspecies 

 globularia, fertile, corolla funnelform, 2.5 to 3.5 mm. long, 5-toothed, villous to glabrous 

 or granular; style-branches truncate, those of the disk-flowers commonly dilated and erose 

 at summit; achenes nearly cylindric but with mostly raised ribs, truncate or with a 

 slight rim at summit, glabrous but usually granuliferous. 



Widely distributed in northern and mountainous regions, Arctic shores of North 

 America (at least as far east as Camden Bay) to the Rocky and Sierra Nevada Mountains, 

 northwest to Bering Sea and Siberia; also in Scandinavia. 



SUBSPECIES. 

 There is a very considerable range of variation in the size of the plant, the branching 

 of the inflorescence, and the amount of pubescence. The number of recognizable 

 variations is not so great, however, as the long list of described segregates would seem 

 to indicate. This is because the latter have been too often based upon pubescence and 

 other characters which are strongly fluctuating, even over small geographic areas. 

 The more striking variations in North America are the following: 



Key to the Subspecies of Artemisia norvegiea. 

 Heads in elongated spikes, racenies, or panicles. 



Inflorescence open-paniculate or loosely racemose; plants mostly 2 to 5 dm. high; pubes- 

 cence villous or wanting. 

 Leaf-blades mostly less than 4 cm. long, short-oblong or roundish in outline; invo- 

 lucre 5 to 6 mm. high. (Not American; included for comparison only.)' Typical A. norvegiea. 



Leaf-blades mostly over 4 cm. long, elongated-oblong in outline; involucre 4 to 5.2 



mm. high (a) saxatilis (p. 58). 



Inflorescence a narrow raceme or somewhat spike-like; plants mostly 2 dm. or less high; 



pubescence usually canescent or appressed silvery-silky (6) heterophylla (p. 59). 



Heads in a dense globoid terminal cluster. Northern dwarf forms sometimes simulated 

 by reduced plants of heterophylla. 

 Lower leaf-blades simply or only 2 times divided; petiole broad, involucre more than 



5 mm. broad (c) globularia (p. 59). 



Lower leaf-blades 2 or 3 times divided; petiole narrow, involucre mostly less than 5 mm. 



broad (d) glomerata (p. 60). 



5a. Artemisia norvegica saxatilis (Besser). — Stems 1.5 to 5 dm. high; foliage 

 varying from merely somewhat pilose (as in the original A. norvegica) to copiously villous 

 (A. saxicola Rydberg, minor variation 9) or, on the other hand, to perfectly glabrous 

 {A. levigata Standley, minor variation 5); lower leaves 5 to 15 cm. long, the blade 

 usually elongated-elliptic or oblong in outline and 2 to 8 cm. long (usually over 4 cm. 

 long), much divided into linear-lanceolate acute lobes; inflorescence openly paniculate, 

 10 to 30 cm. long, sometimes narrow and racemose, especially in Alaskan forms ; heads 

 large, the involucre 4 to 5.2 mm. high; disk-flowers 33 to 75, their corollas 2.5 to 3.5 

 mm. long. {A. chamissoniana saxatilis Besser; Hooker, Fl. Bor. Am. 1:324, 1833). 

 Alberta (and probably farther to the northeast), to the high mountains of southern 

 Colorado, the Sierra Nevada of California, and north through Washington and Alaska 



' Typical A. norvegica should perhaps be admitted to the North American flora. Wille records the species from Green- 

 land (Engler's Bot. Jahrb. 36, beiblatt 81 : 58, 1905), but he did not distinguish between the typical and the American sub- 

 epecies. 



