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

CACTACEA.
5-10, inferioribus albidis, superioribus robustioribus rufescentibus centrali subsingulo robusto
fusco patulo S. deflexo; bacca depresso-globosa, umbilico lato plano, pulvillis sub-25 aculeolos
5-10 breves gerentibus.-(Plate XIV, fig. 4.)
Sent from the Yellowstone by Dr. Hayden. A stout form; joints 3 inches long, 21-24 wide;
pulvilli 4-6 lines apart, the dirty 5ellowish bristles visible only on the older joints. Central
spine single, or only on vigorous specimens on the upper pulvilli 2, mostly brownish, deeper
colored on the margin. Fruit 8-9 lines long, umbilicus, of the same diameter, spines only 1-3
lines long, defiexed. Seed 3 lines in diameter, rim rather narrower than in the first-mentioned
form.
r MICROSPERMA: articulis ut in preacedente; stigmatibus 5; bacca ovata, uimbilico parum depresso, puilvillis, 20-30 setcs51 et breviter aculeolatis, seminibus anguste acuteque marginatis.
(Plate XWV, figs. 5-7.)
On the Missouri, about Fort Pierre; brought down 10 years ago by the fur traders. Very
similar to tl e last form in the general appearance; also with only 1, or at most 2, central dark
spines; flowers only with 5 stigmata, otherwise same as the one described above; fruit short,
oval, with 10-20 very short spines on the numerous pulvilli; seed only 2 lines in diameter, more
regular, thicker in proportion, with a narrow and acute rim. It might be supposed that these
characters were important and constant-enough for a specific difference, if we did not know the
great variability in this genus, and if we did not find among Dr. Hayden's plants seeds of
intermediate shape and size.
8 SUBINERMIS: articulis elongato-obovatis, pulvillis subremotis, inferioribus, inermibus, superioribus aculeos paucos breves gerentibus.
Brought from the Upper Missouri by Dr. Hayden; remains constant in three years cultivation.
Joints 31-5 inches long, half as wide, gradually narrowed down at base; leaves entirely similar
to those of the common form; pulvilli 6-9 lines apart; spines entirely wanting, or on the upper
pulvilli 2 or 3 short and slender ones, rarely one or the others more robust, 1-g inch long;
flowers not seen.
e ALBISPINA: articulis late obovatis, setis stramineis, aculeis omnibus albis gracilioribus, exterioribus 6-10 setaceis, interioribus in pulvillis superioribus 1-3 robustioribus elongatis deflexis
s; patulis; bacca ovata, seminibus magnis. (Plate XIV, figs. 8-10.)
Sandy bottoms and dry beds of streamlets on the Upper Canadian, 250 miles east of the Pecos;
on the Sandia mountains, near Albuquerque; also, on the Upper Missouri. This was the first
form of this species met with in travelling up the Canadian; the stouter and more compact
forms were found further west, in higher elevations. Joints 3-4 inches long, 2a-3 wide; pulvilli 4-6 lines apart; spines all ivory white, rarely with a yellowish tinge, larger ones 1 — inch
long; fruit with very shallow umbilicus, and very slender and short spines; seed 3-3 lines in
diameter, irregular, rim broatd acutish. A form from the Sandia mountains with puivilli more
remote; spines longer, more slender, some of them fiexuous; seems to unite this with the next
variety.
: TRICHOPHORA: articulis ovatis, pulvillis confertis parce albo-tomentosis setas stramineis
demun albidas breves gerentibus, omnibus armatis; aculeis 10-18 setiformibus albis, exterioribus 8-12 brevioribus radiantibus, interioribus longioribus defiexis, rarius singulo suberecto;
pulvillis in articulis vretulstioribus ligno sis confertissimis setas numerosas aculeosque 15-25
capillaceos elong~atos flexuosos gerentibus; bacca ovata, umbilico parum immerso pnlvillis 35-40
albo-tomentosis stramineo-setosis fasciculum aculeolorum 12-18 plerumque defiexorum gerentibus;- seminibus maximis valde cQmpressis irregularibus latissime acuteque marginatis. (Plate
XV, figs. 1-4.)
Only on the volcanic rocks about Santa Fe, and on the Sandia mountains. The hoary appearance of the older joints is very characteristic, and reminds one strongly of Pilocereu8 8enilis.
These hlairs are from a few lines to 2 or 2~ inches in length, and of the appearance and about as
46