MR. GEYER'S ROCKY MOUNTAIN PLANTS. 245 
Rays saffron-yellow. May, June. (n. 395.)—This noble 
specimen affords but a solitary expanded flower, which, 
without destruction, cannot be dissected to determine the 
Genus. Mr. Geyer was disposed to refer it to Espeletia, 
Nutt., (Balsamorhiza) ; but it accords better in habit with 
Silphium. Mr. Geyer speaks of the leaves as “stiff;” 
rendered so perhaps by gummy exudation, for they are, 
when dry, peculiarly thin and papyraceous for a plant of 
this group: the plant is too everywhere glabrous. The 
root-leaves are about a span long, on short broad footstalks, 
and there is a singular contraction below the middle, 
whenever they become decurrent into the petiole, which 
did not escape the notice of Mr. Geyer. The flowers are _ 
large: the rays, in a dried state, orange-yellow : the i invo- - 
TR almost hemisphærical, of many imbricated, but 
not close-pressed membranous striated and reticulated 
scales. 
1. Iva axillaris, Ph. Nutt.—Hook. Flor. Bor. Am. 1. P. 30% - > 
_t. 106. Torr. et Gr. Am. 2. p. 287. p 
Han. Saline clayey slopes of the high calcareous bills af 
Upper Platte; in such situations it isa small shrub, i in 
_Saline swampy meadows and in drift sand it assumes an ere 
.. habit and is herbaceous. Fragrant. July. (n. 159.) 
1. Ambrosia artemisiefolia, L.—Torr. et Gr. Am. 2. p 
À. elatior, L.—Hook. FI. Bor. Am. 1. p. 309. : 
ean A: Water-courses, Spoks mr rare, July. (n. 2 
= ranseria Haiii, N PE e: et Gr. Ad. 2.0. 294 
- Ambrosia acanthocarpa, Hook. Fl. Bor. Am. 1. p. 309. - 
AB. Growing with 4 Iva axillaris in the drift-sand, p! ia 
d -walla River. August. (n. 652.) — 
