370 BOTANICAL GAZETTE | DECEMBER 
to that natural botanical region of which Wyoming, with its high 
arid plains and mountain ranges, is the center. Localities men- 
tioned are in Wyoming unless otherwise stated. 
CHRYSOTHAMNUS GRAVEOLENS Nutt.— For the literature of 
this species and a thoroughly usable characterization see Erythea 
.3: 108. 1895. Its range as there given, and the habitat, ‘‘ denu- 
dated soils,” given by Nuttall, will prevent confusing with this 
certain other species that have been too often included. Thor- 
oughly typical are the following collections: George E. Oster- 
hout, New Windsor, Colo., September 8, 1898; the writer’s nos. 
503 and 2758 from the Platte cafion, in 1894 and 1896. 
CurysotHamnus PLatrensis Greene, Pitt. 4:42. 1899. C 
speciosus Plattensis Greene, Erythea 3: 111. 1895.—This is the 
representative in this range of the far northwestern C. spectosus 
Nutt.2_ I know of no specimens except from the eastern base of 
the Rockies. Well represented by the following collections: 
C. S. Crandall, Fort Collins, Colo., September 17, 1898; George 
E. Osterhout, New Windsor, Colo., September 8, 1898; E. L. 
Greene, LaSalle, Colo., September 10, 1896; the writer, Chey- 
enne, Wyo., August 27, 1896. 
Chrysothamnus pulcherrimus, n. sp.—Shrub 0.5- 
tree-like in form (a short trunk-like base much branched above); 
main stem and branches with grayish bark, the season's stems 
yellow but under the lens minutely lanate-puberulent, rather 
slender-virgate, terminating in an ample, compact, paniculate 
cluster: leaves moderately numerous, narrowly linear, rather 
‘=> high, 
lax and spreading, 5-8 long, from white-tomentose to green: | 
ish-glabrate: involucral bracts only two or three in each row, 
oblong, acute, nearly glabrous, ciliate on the margins: corolla 
tube longer than the throat into which it gradually ¢€ 
rather closely short-hairy : anthers well exserted, the append- 
ages of the style exceeding these: akene softly pubescent. 
A handsome shrub, its arboreous habit, numerous, slender pranchlets, 
large trusses of bright yellow flowers make it one of the strongly ore 
ized and conspicuous species. It is to be distinguished from C. graven" 
but I believe 
xpands, 
and 
2 This and its var. albicaulis is sometimes reported from this range, 
cannot be authenticated. 
