CACTACEiE. 
41 
9. Op. tortispina (sp. nov.): prostrata articulis majusculis adscendentibus obovato-orbiculatis 
pulvillis subremotis stramineo s. fulvo-setosis ; aculeis 3-5 majoribus compressis angulatis 
subinde canaliculatis saepe spiraliter tortis, albis basi apiceque smpe corneis, adjectis infra 
aculeolis 2-3 gracilibus albis ; flore-; bacca ovata areolis sub-20 parvulis notata, late 
umbilicata, seminibus mujusculis regularibus crassis. (Plate Y, fig 2-3.) 
On the Camanche plains, near the Canadian river, east of the plateau of the Llano Estacado. 
Similar in growth to the more western 0. Camanchica. Joints rounded, 6-8 inches long ; 
pulvilli 1-llj inches apart; bristles short, except on the edges, where they are 2-3 lines long, 
but rather slender ; spines more numerous than in any other of our species, with juicy fruit, 
often 6-8, lower smaller ones %-l inch, larger ones 1^-2^ inches long, entirely white or yel¬ 
lowish horn-colored at base and tip ; on the upper areolae one erect spine, the others spreading 
in different directions, lower ones deflexed. Fruit similar to that of last species, large, oval, 
not contracted at base, perhaps less juicy and with a somewhat smaller and deeper umbilicus, 
lf-2 inches long, l-l^- in diameter. Seeds 2-3 lines across, thick and quite regular, with a 
very slight indentation at the hilum. 
I had observed that sometimes 2 plants are produced from the same seed ; this I found to be 
the case occasionally with Opuntia occidentalism Engelmanni and dulcis, one of the young 
plants always much larger and more vigorous than the other. In examining different seeds of 
this speceis, I succeeded in finding one with two embryos (see figure), one spirally coiled 
around the other, both together appearing like one large one. 
10. Op. Kafinesquii, Engelm.: diffusa radice fibrosa, articulis mediis s. majusculis obovatis s. 
suborbiculatis per-viridibus ; foliis subulatis elongatis patulis pulvillis sub-remotis albido-s. gri- 
seo-villosis setas graciles rufas demum elongatas gerentibus plerisque inermibus ; aculeis paucis 
plerumque solum marginalibus validis teretibus rectis albidis saepe basi apiceque rufescentibus 
erectis s. patulis, singulis s. uno alterove graciliore deflexo adjecto ; floris alabastro conico 
acuto, ovario clavato pulvillis 20-25 griseo-villosis rufo-setosis instructo ; sepalis tubi sub-13 
oblanceolatis acuminatis, interioribus late petaloideo-marginatis cuspidatis ; petal is 10-13 late 
obovatis eroso-denticulatis sub-marginatis sulphureis basi intus miniatis, stigmatibus 7-8 erectis 
adpressis fluvo-albidis ; bacca ovata basi angustata clavata subnuda pulposa purpurascente, 
umbilicoinfundi buliformi immerso ; seminibus subregularibus compressis, margine plerumque 
lato compresso sub-acuto. Yar. microsperma subinermis seminibus minoribus regularibus 
angustius marginatis. (Plate XI, fig. 1-3.) 
In sterile, sandy, or rocky (consisting as well of sandstone as of limestone) localities in the 
Mississippi valley, Illinois, Missouri, Arkansas, and north to Wisconsin, east to Kentucky, and 
south, probably, to Louisiana and Texas ; westward it has not been found west of the western 
boundary of Missouri and Arkansas. Flowers in May and June ; fruit ripens in the same 
season, but remains on the plant till the following spring. Joints rather large, orbicular 3-4 
inches in diameter, or obovate, 4-5 inches long by 3 in width ; a small variety with orbicular 
joinsts only 2 inches in diameter occurs on sandstone rock in southern Missouri. The color of 
the plant is dark or fresh-green. Leaves 2^-4 lines long, diameter about one-fourth of the 
length ; pulvilli 9-12 lines apart with short whitish or grayish wool, and bright red-brown 
bristles conspicuous even in the youngest joints. Spines rarely none, generally few in var. 
microsperma, sometimes disappearing entirely in fertile soil in gardens, etc.; mostly only on 
the upper part or the edge of the joint, single or rarely 2-3, 9-12 lines long, rather stout, white 
with a darker tip and sometimes also darker base. Flowers 24-3^ inches in diameter, sulphur- 
yellow, mostly with a red centre. Fruit l|-2 inches long, less than half that in diameter, 
narrowed at base, the seminiferous cavity not extending to the base ; umbilicus funnel-shaped, 
but with shallow bottom, much wrinkled and scarred ; naked by the disappearance of the 
bristles of the pulvilli, and edible, somewhat acid or sweetish. Seeds 2|- lines in diameter, 
6 r 
