Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean: Vol. 4, Pt. 3

CACTAOEA.
hardly more than one line in thickness; rim rather narrow, thick, but acutish. Var. MIcros
perma has seeds only 0.8 or 0.9 line in diameter, more compressed, with quite a narrow rim.
this species has, by western botanists, generally been considered identical with the eastern
0. vulgaris. Riddell mentions it as occurring in Kentucky and Illinois, Torrey & Gray in
their Flora do not give any locality in the Mississippi valley; but Rafinesque had already
observed it in Kentucky, and, in his usual careless manner, had indicated 3 species: C~ctus
7humufusus, (which growing, "from New York to Kentucky and Missouri," probably comprised
both O. vulgaris and our species,) O. ccespitosa, from Kentucky and Tennesse, and O. Mesacantha, from Kentucky to Louisiana. As it seems impossible from his incomplete descriptions
to make out what he meant by three different names, and as we know only one species in those
States of the Mississippi valley, I take the liberty of discarding those names and of substituting
the name of the author for the western species. It is not improper to state here that Rafinesque's vague and partly erroneous descriptions have found their way into Seringe's Bulletin,
1831, page 216, into the Linnea, vol VII[, into Pfeiffer's Enumeratio Cactearum, page 146,
and into other works, but with the substitution of Nuttalls for Rafinesque's name as authority;
the "rounded joints" have, in these works, been taken for " globose" or "cylindric" joints,
and our plant has been classed with the Opu aice glomerate from Chili and Mendoza.
A large form of O. Bafinesquii was coll cted near Fort Smith, on the western border of
Arkansas; further west, where no true O. -R{finesquii has been found, several forms were met
with, which, though they exhibit some distinctive characteristics, are, perhaps, not sufficiently
different to constitute distinct species. The-fiowers of most of them are unknown as well as
the leaves, but fruit and seed were carefully preserved, which not only furnish important
characters, but also the means to propagate, cultivate, and further to study them. We append
them as sub-species.
1. RADICE FIBROSA.
a. O. CYMOCHILA: diffusa articulis orbiculatis pulvillis subremotis griseo-tomentosis stramineo
s. fulvo-setosis, plerisque armatis; aculeis 1-3 robustioribus elongatis teretibus s. subcompressis
tortisque albidis basi saepe rufescentibus, patulis deflexisve, additis saepe 2-3 gracilioribus
radiatim deflexis; flore? stigmatibus 8; bacca obovata umbilico plano S. parum depresso pulvillis 20-24 griseo-tomentosis parce setulosis, demum nudatis; seminibus irregularibns angulosis
margine undulato acuto. (Plate XII, fig. 1-3.)
On the Camanche plains east of the Llaio Estacado, near the 100th degree of longitude, and
from there to Tucumcari hill, 80 miles east of the Pecos. Joints 21-3 inches in diameter,
orbicular or very slightly obovate; pulvillis 6-8 lines apart; the very light yellowish-brown
bristles numerous, and conspicuous only on the older joints; only the lowest pulvilli of a joint
unarmed, upper ones with 2-5 spines, 2 or 3 larger ones, often reddish-brown at lower half, 1-2
inches long, lower, smaller, paler ones 3-9 lines long. Fruit oval, 1-1-1 inches long, about
10 lines in diameter, purplish, pulpy, sweet, and edible, less contracted at base than O. 0aynesquii; seed remarkably irregular and twisted, 21 lines in diameter, with a wavy or twisted
very sharp rim, whence the name which indicates the undulated border.
The orbicular joints, the numerous spines, thd oval not clavate fruit, and curiously twisted
seed, seem to distinguish this form sufficiently from O. Rafinesquii, but these characters may
not be sufficiently constant or important to constitute specific difference. The characters of
Opuntie are not yet sufficently studied to permit us to form satisfactory conclusions about their
diagnostic importance; so we find a form collected on the Sandia mountains, near Albuquerque,
which, in habit and appearance, does not differ from the common form of 0. Rafinesquii, but
which has the seeds of O. cymoch7ila.
0. CYMOCHILA,. MONTANA: articulis orbiculatis majoribus inermibus s. margine superiore
solum aculeatis; pulvillis remotis stramineo-setosis; aculeis singulis binisve validis albidis
42