Nelson : Ni:\v Plants from Wyoming 485 



Artemisia Natronensis. 



A. Ludoviciana integnfolia Aven Nelson, First Rep. Fl. Wyo. 



138. 1896. I- 



Stems herbaceous, from a woody p2rsistent crown, suberect, 

 simple, virgate. silvery whitc-tomeiitose as arc also the leaves, flori- 

 ferous for nearly half their length, 3-6 dm. high : leaves broadly 

 linear to lanceolate, nearly equally tomentose on both sides, in age- 

 the margins revolute, the midrib becoming conspicuous below and 

 the tomentum looser : panicle narrow, its raceme-like clusters in 

 the axils of the leaves which become gradually smaller and bract- 

 like upward or wholly wanting on the summit : heads rather large, 

 campanulate, about 5 mm. high, in small axillary racemes (often 

 only 1-3 heads in each cluster), erect or nearly so even at maturity, 

 about 20-flowered ; the bracts ovate to oval : corolla resinous-dot- 



' I 



ted on the tube only or but sparsely so on the throat and lobes. 



A. Ltuioviciana as represented in the herbaria is, as every one 



knows, a composite. Nuttall's description excludes several forms 



that are often included but are undoubtedly distinct. The species 



r 



now proposed is one of the forms that I think is clearly separable by 

 valid characters. Possibly it may be A. integnfolia Pursh but 

 that name'ismuch antedated. That it is A, Pursliiana Bess, or A, 



Hookeriana 



From 



r 



A. Ludoviciana its entire leaves, narrow, virgate panicles, large 

 erect heads and broad involucral bracts distinguish it. The num- 

 erous small, crowded heads of the inflorescence o( A. Ludoviciana 

 are on more or less recurved pedicels and the florets are smaller 



and resin -dotted throughout. 



Type no. is 568, Willow Creek, July 20, 1894, distributed as 

 a variety of A, Ludoviciana as given above. Excellent specimens 

 have been collected by Mr. Flias Nelson, Wallace Creek, July -^o, 

 1898, no. 5002 — from Natrona county, whence the name. 



Malacothrix runcinata ' J 



Annual or possibly biennial, leafy on the crown and sparingly 

 so on the stems, mostly glabrous and somewhat glaucous, rarely 

 with small patches of woolly pubescence : stems one to several 

 from the crown of the slender tap-root, erect or, when several, 

 decumbent at base, 5-15 cm. long: leaves rather small, 2-4 cm. 

 long, oblanceolate to linear in outline, from dentate to runcinatc : 

 heads one to several on each stem. 8-12 mm. hiMi : involucre 



