274 Nelson: New Plants from Wyoming 



less apparent as they grow older so that in the herbarium they 

 may finally be devoid of odor. 



The range of this species, as represented by the material be- 

 fore me, is the north-central Rockies, but it probably is more 

 widely distributed. Nos. of the past season may be cited as typical 

 as follows : 6602, Yellowstone Lake ; 6804, Henry's Lake, Idaho ; 

 6903, Laramie Hills. 



Artemisia nova 



The shrubby base low, scraggy-branched, prostrate spreading, 

 rarely 1—2 dm. high, with grayish, shreddy bark : the herbaceous 

 stems (season's growth ?) very numerous, fascicled, slender, simple, 

 leafy below the inflorescence, 1-2 dm. high including the narrow 

 spike-like panicle, grayish with a thin tomentum, or mere pubes- 

 cence as also are the leaves : leaves very narrowly cuneate, 1-2 

 cm. long, 3-toothed at apex, the middle tooth usually longest : 

 panicle leafy at base, naked above, strict and nearly simple : heads 

 small, very numerous, only 3-4 mm. long, usually 3-flowered but 

 often only one or two : involucral bracts closely imbricated, green- 

 ish, only slightly puberulent : akenes glabrous, resinous dots on 

 the tube of the corolla only. 



That this species has so long escaped detection can only be 

 accounted for on the assumption that it was a depauperate form of 

 the common sage-brush {Artemisia tridentatd). That such was 

 not the case has been a growing conviction with me for some time. 

 A critical examination leaves no room for doubt. The impres- 

 sions made in the field * that this is constantly a dwarf form with 

 simple, slender, fascicled stems and greenish inflorescence, is con- 

 firmed by differences in floral characters. The few-flowered in- 

 volucre and the differences in pubescence are conclusive and 

 separate it also from A. arbuscula, from which it is equally well 

 separated by its leaves. It occurs on hillsides and ridges either 

 on the plains or in the foothills. 



Collected as follows: 4095, Medicine Bow, Aug. 11, 1898; 



fc> 



5272, Centennial Valley, Aug. 30, 1898; 5334, Laramie, Sept. 

 14, 1898. 



* Mr. Elias Nelson when collecting one of the numbers of this made the following 

 field note: "Occurs on open hills and ridges, never in the draws but always in ex- 

 posed places ; very different from A. tridentata in habitat and general appearance, being 

 greener in color and always a low shrub." 



