ARTEMISIA 



COMPOSITE 365 



ers 1-4, with truncate corolla ; the hermaphrodite sterile flowers 4-8, their 

 corollas ventricose-cainpanulate from a narrow base, 5-toothed : achenes 

 oblong-ob ovate. On alkaline plains, southeastern Oregon to California 

 Wyoming and Idaho. 



* * Perennial herbs without spines: heads many-flowered; recepta- 

 cle hemispherical or ovate : achenes nearly glabrous. 



A. Canadensis Michx. Fl. ii, 129. Glabrous, or mostly with at least the 

 radical and sometimes all the leaves either sparsely or canescently silky- 

 pubescent: stems 1-2 feet high from a perennial root : leaves mostly bipin- 

 nately divided into linear or almost filiform divisions: heads very numer- 

 ous, 1-2 lines long, in a compound oblong or pyramidal virgate panicle : 

 involucre greenish, glabrous, or rarely pubescent. On rocky banks and 

 plains, Brit. Columbia to California and the Eastern States. 



A. Groenlandica Wormsk. Fl. Dan. t. 1585. Stexis simple, 10-16 inches 

 high from a stout perennial caudex : leaves silky-pubescent, radical and 

 lower cauline 1-2-ternately or pinnately divided into linear lobes; upper- 

 most linear and entire or 3-parted: heads numerous, in a somewhat loose 

 narrow thyrsus: involucre pilose or glabrate, pile fuscous or brownish. 

 On wet banks, Washington to Alaska and Hudson Bay. 



A. pedatilida Nutt Trans. Am. Phil. Soc. vii, 399. Canescent through- 

 out with a fine and close pubescence: cespitose with stout lignescent cau- 

 dex, very dwarf : leaves chiefly crowded in radical tufts and on the base of 

 the rather naked flowering stems, once or twice 3-parted into narrowly- 

 spatulate or nearly linear obtuse entire divisions : heads few, loosely spicate 

 or racemosely disposed, canescently pubescent, 12-15 flowered; the herma- 

 phrodite sterile flowers with style barely 2-lobed at summit and no ovary. 

 Arid grounds, Idaho and Wyoming to the Rocky Mountains. 



A. dracnneuloides Pursh Fl. ii, 742. Glabrous; stems 2-4 feet high 

 from a perennial root, vimately or paniculately branched: leaves mostly 

 entire, some of the lower ones 3-cleft or more divided, linear, 1-4 inches 

 long: heads very numerous, in a compound and crowded or open and diff- 

 use panicle : involucre nearly hemispheric, its bracts ovate or oblong, green, 

 scarious- margined : receptacle hemispheric, naked. Dry plains, British 

 Columbia to California Texas and Nebraska. 



§ 2 Euartemisia Gray Syn, Fl. i, pt. 2, 369. Heads heterogam- 

 ous ; the disk-flowers harmaphrodite and fertile, with 2-cleft style. 



* Achenes obovoid or oblong, wholly destitute of pappus : receptacle 

 beset with long woolly hairs. 



A. frigida Willd. Sp. iii, 1838. Silky-canescent and silvery : herbace- 

 ous from a suffrutescent base, about a "foot high; simple or branching, 

 numerous racemously disposed heads in an open panicle : leaves mainly 

 twice ternately or quinately divided or parted into linear crowded lobes, 

 and usually a pair of simple or 3-parted stipuliform divisions at the base 

 of the petiole : heads globular, barely 2 lines in diameter ; involucre pale, 

 canescent, its bracts narrow and herbaceous: corollas glabrous. Idaho to 

 Nevada Texas Minnesota and the Saskatchewan. 



* * Achenes obovoid or oblong, with small epigynous disk, wholly 

 destitute of pappus : receptacle not villous. 



A. biennis Willd. Phytogr. 1794, 11. Annual or biennial : wholly glab- 

 rous and inodorous: stems strict 1-4 feet high, with nearly erect branches, 

 very leafy, bearing close glomerules of small heads in the axils from near 

 the base of the somewhat naked and spiciform summit: leaves 1-3 inches 

 long, 1-2-pinnately parted into lauceolate or broadly linear laciniate or 

 incisely toothed lobes ; or the uppermost small, sparingly pinnatifid and 



