436 
EXPLOEATIONS ACROSS THE GEEAT BASIX OF UTAH. 
crowded at the end of lateral branchlets, a few lines to 1 or 1 \ inches in length closely 
covered with circular scars. Leaves very thick and leathery, persistent, lanceolate, 
acute at both ends, entire and revolute at the margin, with a thick midrib, prominent 
on the lower surface, 9-14 lines long, 2 J-3 J lines wide, on a petiole 1J-2 lines long, 
to the lower part of which adhere lanceolate, brown, scarious stipules. When youngs the 
branchlets as well as the leaves are covered all over with short, curly hair; when older, 
the leaves become glabrous and glossy on the upper surface, the lower remaining hairy 
and assuming a rusty color. The sessile flowers are produced in June from the 
axils of the uppermost leaves of the preceding year’s growth, either single or 2 or 3 
together; short scarious bracts envelop the base of the cylindrical woolly calyx-tube, 
which is 3 lines long; its 5-lobed, white limb, 3-4 lines in diameter, is very woolly 
externally, and less so internally, and bears about 20 or 25 naked, slender filaments^ 
with reniform anthers \ line in diameter. Immediately after flowering, the silky-feathery 
style becomes elongated, and carries up with it the detached limb of the calyx; at 
maturity, the style becomes a twisted, feathery tail of about 2 inches in length; the 
inconspicuous, linear, hairy fruit itself is about 4 lines long, and remains hid in the 
persistent, calyx-tube; at its top and base I observe a beard of very curious, stiff, white 
bristles, less than a line in length, thicker in the middle, and tapering toward both ex¬ 
tremities* The fruit seems to be somewhat persistent, as I find it in specimens collected 
in spring before the flowering-season. About the time of flowering, the young leaves 
begin to develop at the end of the branchlets, leaving the flowers between them and 
the leaves of the year before. I generally find 4 or 5 leaves of the same year’s growth 
at the end of each branchlet; they probably fall off when about 15 or 18 months old. 
This fine tree, discovered by Nuttall on Bear River, north of the Salt Lake, and 
Hear “Thornberg’s Ravine” in the Rocky Mountains, was found by the expedition on 
the Lookout Mountains and other mountain-chains of the basin. 
CACTACEiE. 
of the area of this curious American family have been 
considerably enlarged by this expedition, proving the presence of at least 7 species in 
the Utah Basin between the thirty-eighth and fortieth parallels, viz: 2 Echinocacti, 1 
Cereus, and 4 Opuntise. Several species known before have been found in new local¬ 
ities, and 3 new and very distinct species have been discovered, 2 Echinocacti and 1 
Opuntia. 
Mamillaria vivipara, Haworth , Suppl p. 72; Torrey & Gray, FI. N. Am . 2, p. 
. 554; Fngelm. Synops. Cad. p. 13; Cactus viviparus, Nuttall , Gen. 1, p. 295. 
Was collected in the South Pass and on Sweetwater River. It extends from here 
to the mountains of Colorado and Ne^ Mexico, but its most characteristic forms are 
peculiar to the more elevated plains, where it assumes that cespitose, spreading appear¬ 
ance, from which it has received its name. The mountain form usually makes larger 
heads, but remains single or branches out very sparingly. Its large purple flowers, 
with numerous lance-linear, long acuminate, bristle-pointed petals, and its leather- 
brown pitted seeds, readily distinguish it from allied species. 
The geographical limits 
cm 
2 3 4 5 6 7 8 9 10 
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