588 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



7. Artemisia ludoviciana Nutt. Gen. 2: 143. 1818. 

 Artemisia gnaphalodes Nutt. loo. cit. 



Artemisia diver sifolia Rydberg, Bull. Torr. Club 28: 21. 1901. 



Type localitt: "On the banks of the Mississippi, near St. Louis; also on the alluvial 

 plains of the Missouri." 



Range: British Columbia to Michigan, south to California and Texas. 



Specimens examined: Lake Chelan, Lake cfr //)///, August 12, 1892; Wenache, Whited 

 1338, 11; Yakima, Watt, August, 1895; junction Crab and Wilson creeks, Samlherg A 

 Leiherg 337; Sprague, Lake cfe Hull 725; Spokane, Pifer 3519; Elmer S(>7; Pullman, 

 Piper 1.586; Salmon River, Homer 342; Rock Lake, Ixike cf- Hull 724; Coulee City, Uke 

 cfe Hull, August, 1892; west Klickitat County, Svksdorf 1(510; Toppenish, Cotton 778; 

 EUensburg, Elmer 378; Ijake Chelan, Gorman 679; Sheep Springs, f^iberg 944; Walla 

 Walla, Wilkes Expedition 944; Fort Colville, Watson 227; Blue Mountains, Homer 296; 

 without locality, Vawj/ 479, 482; Squaw Creek, Cotton 867. 



Zonal nisTuini'TioN: Arid Tran.sitioii and l^pper Sonoran. 



An exceedingly common species pres<»nting great variability as to leaf contour and 

 pulH'scenc<». Several such forms have Ix^en considered species or subspecies, a disposition 

 which seems to us entirely artificial. The plant is often called " white sage." 



8. Artemisia atomifera sp. no v. 



Cespitose, often in large clumps; stems sufTrutesccnt, mostly simple up to the inflores- 

 cence, 60 to 120 cm. high, coarsely striate, canescent or glabrate; leaves numerous, sub- 

 sessile, firm, and rather rigid, green and nearly glabrous above, speckled with numerous 

 white resinous atoms, closely white-tomcntose beneath, exce^ssively variable as to form, 

 either all lanceolate and entire or all dentate or laciniate, or the larger ones 5 to 7-pinnately 

 divided with narrow 1o1k>s, usually the upper one,s entire, the lower variously dentate or 

 lolled, connnonly 2 to 6 cm. long; panicle oblong or somewhat pyramidal, 10 to 20 cm. long, 

 more or less leafy-bracted, the heads glomerate or spicate on the ascending branches; 

 involucre campanulate, cancscently tomentose, mo^^ or less atomifcrous like the leaves, 2 

 to 4 cm. high; bracts almut 10, ovate, obtuse; flowers 10 to 25 in each head; mature 

 akene-s linear-oblong, glabrous, destitute of pappus. 



A species with the habit and appearance of A. ludoviciana Nutt., to which it is cl sely 

 allied, but apparently well marked by the peculiar atomiferous character of the upper leaf 

 surface. The odor is decidedly more pungent than that of A. huhviciana. I have never 

 met the species except in Snake River canyon at Wawawai and Almota. 



The typ<^, in the U. S. National Herbarium, is my no. 640() from Wawawai, a good scries 

 of which shows the variability of the foliage. Other specimens were collected at Wawawai 

 July 19, 1892, and at Almota under no. 2321. 



9. Artemisia tilesii Ledeb. Mem. Acad. St. Petersb. 6: 568. 1815. . 

 Artemisia tilesii elatior Torr. & Gr. Fl. 2: 422. 1843. 



Artemisia arachnoidea Sheldon, Bull. Torr. Club 30: 310. 1903. 



Type locality: "Hab. in Kamtschatka." 



Range: Alaska to Oregon. 



Specimens examined: Mount Stuart, Elmer 1199; Cascade Mountains, Tweedy <& 

 Brandegee 115, 469; west Klickitat County, Suksdorf 871; Lake Chelan, Lake <& Hvll, 

 August 24, 1892; Olympic Mountains, Piper, August, 1895; Lake Cushman, Piper, August, 

 1895; Peshastin, Sandberg cfc Leiberg 492; Twisp River, Whited, July 20, 1896; near Van- 

 couver, Sheldon 11284. 



ZloNAL distribution: Hudsonian and Canadian. 



The type of A. arachnoidea Sheldon seems to me only a form of this variable species. 



10. Artemisia discolor Dougl.; DC. Prod. 6: 109. 18:37. 



? Artemisia michauxiana l^o.ssor, Ahrot. 71. 1834. "Ad fluv. Columbiam. Douglas." 

 Artemisia stenoloba Rydberg, Mem. N. Y. Bot. Gard. 1 : 432. 1900. 



