48 BOTANY OF DR. A. WISLIZENUS’S EXPEDITION 
Towards El Paso a curious capparidaceous plant was collected, which appears to be nearly allied 
to the Californian Oxystylis of Torrey and Fremont, and forms with it a distinct group in that family, 
approaching very closely to Crucifere, as has been remarked by Professor Torrey. 
1 have named this new genus (in honor of its discoverer, who has, though unaided and often 
embarrassed in different ways, done so much towards the advancement of our knowledge 
of those northern provinces of Mexico —the first naturalist, it is believed, who explored [99 (15) ] 
the regions between Santa Fé, Chihuahua, and Saltillo) Wislizenta! From Ozxystylis it 
is principally distinguished by its long stipitate ovary and capsule, which latter is reflexed, and by 
the elongated racemes; it may, however, have to be united with that genus. 
On the mountains about El Paso, another of those cylindraceous Opuntia was found, but much 
thinner and more slender than both species mentioned previously. To judge from an imperfect 
description, it must be nearly related to the Mexican O. virgata, Hort. Vind. I have 
given it the name of 0. vaginata,® as the straw-colored loose sheaths of the long spines [100 (16)] 
are very remarkable. A new Echinocereus was also collected here, which, on account of 
its dense covering with small spines, I have named Z. dasyacanthus.” I have in cultivation one of 
at that stage of the growth. Soon after they probably adhere in the centre to each other, and towards the ripening of 
the capsule detach themselves from the valves, presenting a free central triangular spongy placenta, with about 6 (or 
by abortion less) seeds. Capsule coriaceous oval, acutish, light brown, about 6 lines long. Seeds compressed, integ- 
ument expanded in a wing, which is cordate at the upper end, and finally resolves itself into a coma of silky fibres. 
If my view of the ovary and fruit of this plant is correct, the ovary is l-celled, with 3 lateral placentae —that of a 
true Fouquiera, the ripe capsule is 1-celled, with one central placenta —that of Bronnia, and the unripe fruit must be 
3-celled! Fouquwiera splendens grows readily from cuts, and is used about Chihuahua for hedges and fences. 
17 WISLIZENIA, n. gen. Sepala 4; petala 4 oblonga, breviter unguiculata ; stamina 6 toro cylindrico inserta ; fila- 
menta filiformia longe exserta estivatione inflexa; ovarium longe stipitatum, globose didymum, biloculare, loculis 
2-ovulatis ; stylus subulatus, elongatus, stigma globosum. Capsula siliculeformis, didyma tuberculata cum stipite in 
pedicellum filiformem refracta, bilocularis, loculis plerumque per abortum 1-spermis; valve urceolate a dissepi- 
mento pertuso solute, semen includente; semen conduplicato-reniforme, leve; cotyledones radicule super@ 
incumbentes. 
A glabrous New Mexican annual, much branched, of the habit of Cleomella, with ternate leaves, distinct laciniate- 
fimbriate stipules, and bracted at last elongated racemes, small yellow flowers; fruit reflexed, stipe with the equally 
long (not spinous) style, and the small dissepiment persistent after the falling off of the valves. 
REFRACTA, n. sp. On the upper crossing of the Rio Grande, near El Paso ; flowers and fruit in August. An 
interesting and quite anomalous plant, on account of its fruit with an almost complete dissepiment, and of its stipules 
and bracts. Tuberculated valves of the capsule separating from the placenta, and though open, retaining the only 
(rarely two) seed-placentz forming a complete dissepiment, which, in the perfectly ripe and dry state, finally becomes 
perforated in the centre. 
18 OPUNTIA VAGINATA, n. sp.: caule lignoso, erecto, ramulis teretibus vix tuberculatis; areolis orbiculatis, albo- 
tomentosis, margine superiore fasciculum setarum brevium fuscarum, inferiore aculeum elongatum corneum vagina 
laxa straminea involutum, deflexum gerentibus; floribus parvis, ovario obovato, areolis 13 tomentosis setigeris stipato ; 
sepalis interioribus 8 et petalis 5 obovatis mucronatis; bacca obovata profunde umbilicata, carnosa, aurantiaca 5 
seminibus paucis. 
On the mountains near El Paso; in August in flower and fruit. Belongs to Opuntic cylindracec graciliores 
(Salm-Dyck); perhaps nearest to 0. virgata, H. V., but distinguished by the longer deflexed spines. Apparently 
3 or 4 feet high; ultimate branches 23 to 3 lines in diameter ; spines single, 1} to 2 inches long, rarely with a second 
smaller one, straight, more or less deflexed ; epidermal sheath yellow or brownish, very loose, at last coming off 
ovary 4 to 5 lines long; flower 6 to 9 lines in diameter, pale yellow, with a greenish tinge ; stigma conic, with 
5 adpressed segments ; fruit 7 to 8 lines long. ; 
19 ECHINOCEREUS DASYACANTHDS, n. sp.: ovato-oblongus, s. subcylindricus, 17-18 costatus, costis tuberculatis 
subinterruptis, areolis approximatis, ovato-lanceolatis, junioribus albo-villosis ; aculeis albidis, junioribus apice rufidis, 
radialibus sub-18 porrectis, summis brevioribus tenuioribus, lateralibus inferiorilusque longioribus ; centralibus 
pluribus deflexis. 
El Paso del Norte. The specimen before me —one of the largest — is 12 inches high, and 3} inches below and 
2 inches above in diameter; wool on the young areole unusually long, deciduous; upper spines 3 lines long, 
= i el a ae Ta ae eae 
