154 GENUS ARTEMISIA. 



restriction to poor, stony soils over a limited area from western Montana to eastern 

 Washington, where there is a deficiency of rainfall in summer and the winters are com- 

 paratively cold and bleak. 



The original reference of this species to a variety of A. trifida by Nuttall was due to 

 the incomplete nature of the type specimens. These were in leaf only and were thus 

 wanting in the only characters whereby rigida may be readily distinguished. 



ECOLOGY AND USES. 



Artemisia rigida is a low shrub with deciduous leaves. Its stature and leaf habit 

 correspond with its position on thin or stony soil under a low rainfall. It frequently 

 alternates with tridentata where deeper soils permit the growth of the latter. It tends to 

 form pure communities with few or no secondary species. 



The scant foliage is browsed somewhat by sheep, but it is so well protected by the 

 stiff branches and the species is of such limited distribution that A. rigida is of almost 

 negligible importance as a browse shrub. It is probably a cause of hay-fever, especially 

 in Oregon. 



28. ARTEMISIA PYGMAEA Gray, Proc. Am. Acad. 21 : 413, 1886. Plate 22. 

 Pigmy Sagebrush. 



A depressed shrub less than 2 dm. high, the odor unknown; stems flexuous at base, 

 with numerous short, erect branches, the old bark dark brown and fibrous, the twigs 

 pale or nearly white, not striate, puberulent; principal leaves sessile, oblong to obovate 

 in outline, with linear base, 0.2 to 0.5 cm. long, pinnately 3- to 7-parted or with as many 

 divergent teeth, the linear segments obtuse but mucronate, rigid, green, nearly glabrous, 

 more or less viscid; upper leaves smaller, 3-parted or 3-toothed, those of the inflores- 

 cence mostly entire and all shorter than the heads; inflorescence spike-like, 1 to 4 cm. 

 (or more?) long, about 0.5 cm. broad; heads homogamous, sessile, erect; involucre at 

 first nearly cylindric, later spreading and campanulate, 4 to 5 mm. high, about 3.5 to 4 

 mm. broad; bracts about 15 to 20, all similar but the outer ones regularly shorter, 

 linear or linear-spatulate and obtuse, or the outer ones lanceolate and somewhat acute, 

 yellowish-green, with narrow and very thin white-scarious margins, sparsely villous or 

 nearly glabrous; ray-flowers wanting; disk-flowers 3 to 5 (or more?), fertile, corolla 

 turbinate, 4- or 5-toothed, 2.5 to 3 mm. long, glandular at least on the tube; style- 

 branches flat, truncate, fimbriate at summit; achenes ellipsoid, truncate at summit, 

 obscurely angled, glabrous. 



Known only from eastern Nevada and western Utah. Type locality, Desert region 

 of Nevada, at Fisk [Fish] Creek near Eureka. Collections: Type collection, August, 

 1885, Brandegee (Gr, UC); Pioche, Lincoln County, southeastern Nevada, August 31, 

 1912, Jones (UC); Ortons Ranch, Utah, Jones 5984 (NY). 



RELATIONSHIPS. 

 This species differs from all others of its group in having the lower leaves pinnately 

 parted into lateral lobes instead of toothed or lobed from the summit. Some of the 

 upper leaves, however, are 3-lobed, very much after the manner of the other species. 

 The ribs of the leaf are quite prominent in the type collection, but in others they are 

 no more conspicuous than they are in some forms of A. tridentata (for example, in sub- 

 species trifida as represented by M. E. Jones's Oroville, Washington, collection. Herb. 

 Univ. Calif. 175975). The aspect of the plant is unique in Artemisia. The low tufted 

 stems, the minute rigid foliage, and the greenish imbricated involucres suggest the 

 appearance of an Haplopappus of the Ericameria section. The technical characters 

 relate it to .4. tridentata and A. rigida, but beyond this its phylogenetic origin can not 

 now be determined. 



