170 Univcrsitij of California Publications in Botany [Vol. 7 



the more nearly jjlabrous nature of the involucre seems to be the most 

 important. As pointed out by Dr. Nelson, it also resembles graveolens, 

 but the narrower leaves are constantly one-nerved and the involucre 

 is not absolutely jrlabrous. C pulcherrimus fasci-culatus A. Nels., 

 I.e., is described as having numerous short branchlets and luimerous 

 rigid leaves only 2 to )} cm. long. It has been collected at Boulder 

 Creek and at Creston, botii of these localities being in Wyoming. 



8. Chrysothamnus nauseosus vai-. frigidus (Greene) comb. nov. 



Chrysothamnus frigidan Cirecue, Eryth., vol. 3, p. 112, 1895. 



Sub-shrub woody only at the base, often nearly prostrate, 2 to 

 6 dm. high, with mostly erect stems, very leafy: twigs whitish with a 

 smooth close tomentum : leaves 2 to 5 cm. long, 1 to 1.5 mm. wide, 

 mostly erect or ascending, white-tomentose : inflorescence cyraose or 

 elongated : involucre about 7 mm. high ; bracts tomentulose and some- 

 what glandular, ciliolate at least at summit: corolla 6 to 7 mm. long; 

 tube puberulent; lobes linear-lanceolate, 1.2 to 1.5 mm. long. 



This variety belongs to the elevated bleak plains of the Rocky 

 Mountain states, is especially common on the Wyoming plateaus, and 

 is said to occur as far north as Alberta. In one collection (Aven 

 Nelson, no. 2787, from Laramie) the corolla-tube is well provided 

 with a long loose cobwebby pubescence, just as in the otherwise very 

 ditferent nmiseosus proper and in Jiololeucus. C. frigidus concolor 

 A. Nels., Bot. Gaz., vol. 28, p. 371, 1899, is a form w^ith yellowish 

 green herbage and somewhat elongated inflorescences. It grows in 

 sandy more or less alkaline soil in Wyoming and Montana. C. pallidus 

 A. Nels., I.e., p. 372, is a form also allied to frigidus and perhaps to 

 be united with it. The twigs are less leafy except near the top, where 

 they are shorter and more crowded ; the herbage is nearly wiiite with 

 a close persistent tomentum. It inhabits alkaline soil in Wyoming 

 and northern Colorado. 



9. Chrysothamnus nauseosus var. plattensis (Greene) comb. nov. 



Chrysatlianuius spcciosus{J') plnttensis Greene, Eryth., vol. 3, p. Ill, 1895. 



Characters as given for frigidus except that the narrower leaves 

 are loosely spreading or even recurved and that oidy the outer bracts 

 are tomentulose. 



A form of the alkaline plains along the eastern base of tiie Rocky 

 Mountains. The type was described as having rather densely woolly- 

 eiliate bracts but in most collections the bracts are onlv obscurely 



