588 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



7. Artemisia ludoviciana Nutt. Gon. 2: 143. ISIS. 

 Artciiii.sia (/it(iji/ial()(li!< Xutt. loc. fit. 



Artemisia diversifolia Rydhoifi, Bull. Torr. Club 28: 21. 1901. 



Type locality: "On the hanks of the Mississippi, noiir St. Louis: also on the alluvial 

 plains of the Missouri." 



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



Specimens examined: Lake Chelan, Lale & Hull, August 12, 1S92; Wenache, Whited 

 133S, II; Yakiina, Watt, x\ugust, 1895; junction Cral) and Wilson creeks, Snndherfj d' 

 Leihcrg 337; Sprague, Lake & Hull 725; Spokane, Piper 3519; Elmer 807; Pullman, 

 Piper 1586; Salmon River, Horner 342; Rock Lake, Lake cfc Hitll 724; Coulee City, Lal-e 

 & Hull, August, 1892; west Klickitat County, Svksdorf IGIO; Toppenish, Cotton 778; 

 Ellensburg, Elmer 378; Lake Chelan, Gorman 679; Sheep Springs, Leiherg 944; Walla 

 Walla, W like s Expedition ^AA; Fort Colville, Watson 227; Blue Mountains, Horner 296; 

 without locality, Vasey 479, 482; Squaw Creek, Cotton 867. 



Zonal distribution: Arid Transition and Upper Sonoran. 



An exceedingly common species presenting great variability as to leaf contour and 

 pubescence. Several such forms have been considered species or subspecies, a di.sposition 

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



8. Artemisia atomifera sp. nov. 



Ccspitose, often in large clumps; stems suffrutescent, 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 Ijcneath, excessively 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 lobes, usually the upper ones entire, the lower variously dentate or 

 lolx'd, commonly 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, canescently tomentose, more or less atomiferous like the leaves, 2 

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

 akenes linear-oblong, glabrous, destitute of pappus. 



A species with the habit and appearance of ^4. ludonciana Nutt., to which it is cl sely 

 allied, but apparently well marked by the peculiar atomiferous character of the uppe:- leaf 

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

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



The type, in the U. S. National Herbarium, is my no. 6466 from Wawawai, a good series 

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

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



9. Artemisia tilesii Ledeb. Mem. Acad. St. Petersb. 5: 568. 1815. 

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



Artemisia arachnoidea Sheldon, Bull. Torr. Club 30: 310. KX)3. 



Type locality: "Hab. in Kamtschatka." 



Range: Alaska to Oregon. 



Specimens examined: Mount Stuart, Elmer 1199; Cascade Mountains, Tn^eedy & 

 Brandeyee 115, 469; west Klickitat County, Snksdojf S7 1; Lake Chelan, Lake cfc Hull, 

 August 24, 1892; Olympic Mountains, Piper, August, 1895; Lake Cushman, Pi/Jcr, August, 

 1895; Peshastin, Sandbery ct Leihery 492; Twisp River, Whited, July 20, 1896; near Van- 

 couver, 5^(f Won 11284. 



Zonal distribution: Hudsonian and Canadian. 



The type of A. arachnoidea Sheldon seems to me only a form of this varial)le species. 



10. Artemisia discolor Dough; IXL Prod. 6: 109. 1S37. 



?Arteiinsia mirliau.riana Be.sser, Abrot. 71. 1834. "Ad fluv. Columliiaiii. Douglas." 

 Artemisia stenoloha Rvdl)crg"MenL N. Y. Bot. Gard. 1: 432. 19(K). 



