56 UNITED STATES AND MEXICAN BOUNDARY. 
leathery, rarely pulpy, throwing off the dead flower, or very rarely retaining it. In a few 
species it is dry and spiny. ; 
17 O. noutnocarpa, E. & B. in Pacif. R. R. Var. 8. Masor: elatior ; articulis elongatis basi 
attenuatis ; tuberculis oblongo-linearibus ; setis tenuibus penicillatis ; aculeis longioribus laxius 
vaginatis paucioribus ; bacca globosa seu basi clavata pulvillos pauciores gerente. 
In the deserts on both sides of the Colorado, and in Sonora, Schott.—This form looks very 
different from the plant collected by Dr. Bigelow, and described in the report of Captain 
Whipple ; but the very peculiar seeds which fortunately have been obtained by both collectors 
prove them to be identical. Dr. Bigelow’s plant is a low straggling shrub; but Mr. Schott’s 
is 4 or 5 feet high, with divaricate branches, joints 8-10 inches long, with elongated tubercles, 
(6-9 lines in length,) fine long bristles, and longer spines with looser sheaths. The 4 central 
larger spines are 1-1} inch long; the 4-8 radiating spines on the contrary shorter ; the 
first is longer and bears only about 25 pulvilli, as spiny as in the original form. 
18. O. serPenTINA, E. in Sill. Journ., 1852: diffusa; ramis elongatis subverticillatis divari- 
catis adscendentibus ; tuberculis prominentibus ovatis; pulvillis albido-setosis; aculeis 7-9 
vaginatis albidis seu rufescentibus porrectis, infimis deflexis ; floribus minoribus flavis extus 
rubellis ; ovario depresso pulvillis sub-20 stipato; sepalis 10 late obovatis breviter cuspidatis ; 
petalis sub-5 obovatis integriusculis mucronatis ; stigmatibus 8 erectis; bacca sicca subhemi- 
spherica villosa aculeatissima late et profunde umbilicata flore emarcido szepe coronata. 
Dry hills near San Diego, California, Parry, generally nearer the seacoast than O. prolifera, 
and not gregarious, nor so common as that species, Schott.—Stems 1-1} inch in diameter, 
suberect, 4-5 feet high, or almost prostrate ; joints 6-12 inches long, 3-1} inch thick, 
somewhat verticillate, divaricate; spines 3-9 inches long, sheathed, light yellowish, or rusty, 
upper ones stellate-divaricate, lower one closely deflexed. A single flower was collected by Mr. 
Schott in October ; it is not quite 14 inch wide, the ovary depressed, about 8 lines high with 
20 areole bearing dirty yellowish wool, yellow bristles, and 5-7 reddish brown sheathed spines, 
2-4 lines in length; sepals externally yellowish-green, tinged with purple ; even the lower 
ones unusually obtuse or short cuspidate ; petals rounded scarcely 9 lines long, yellow above, 
red at tip, ascending and forming a cup-shaped corolla ; stigmata (green ?) 2 lines long. Fruit 
saucer-shaped, deeply and broadly umbilicate, yellowish-brown, very Spiny, and ‘ long 
woolly.’’ é | 
19. O. protirera, E. 1. c.: caule arborescente ; ramis numerosis horizontalibus divaricatis- 
simis ; articulis ovatis seu ovato-cylindricis tumidis fragilibus versus ramorum apicem congestis 
pervitidibus, inferioribus demum refractis brunneis; tuberculis obovato-oblongis prominulis ; 
pulvillis ovatis tomentosis, vetustioribus stramineo-setosis ; aculeis 8-10 obscuris stramineo- 
seu rufo-vaginatis, singulo subcentrali, ceteris patulis stellatis, inferioribus brevioribus ; flore 
rubro ; sepalis late ovatis ; petalis oblongo-obovatis ; stigmatibus erectis ; bacca ovata umbilicata 
aculeolata sepissime sterili proliferaque. 
On arid hills about San Diego, California, near dry beds of streams, forming impassable and 
extensive thickets, Parry, Schott,—These thickets are likened by Mr. Schott to unapproachable 
coral reefs. Stem 2-4 and sometimes even 6-7 inches thick, and 3-10 feet high ; the wood 
forms a reticulated hollow tube with short meshes, which in old plants finally become obliter- 
ated. The tumid joints are 3-6 inches long, 14-2 inches in diameter, clustered at the end of 
