43 
Fouquera, I am enabled to solve the difficulty to some extent, 
and prove the necessity of re-uniting Bronnia with Fouguiera. 
The flower of Fouguiera splendens, as 1 have named the northern 
plant, is that of a true Fouguiera, while the fruit is nearly that 
of Bronnia ! 
Towards El Paso a curious Capparidaceous plant was collected, 
which appears to be nearly allied to the Californian Ozystylis 
of Torrey and Frémont, and forms with it a distinct group in 
that Family, approaching very closely to Crucifere, as has been 
remarked by Professor Torrey. 
I have named this new genus Wislizenia, in honour 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 na- 
turalist, it is believed, who explored the regions between Santa Fé, — 
Chihuahua, and Saltillo. From Ozystylis it is principally dis- 
tinguished 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 cylindra- 
ceous 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. Berol. I have given it the name of O. vaginata, 
as the straw-coloured loose sheaths of the long spines are very 
remarkable. A new “chinocereus was also collected here, which, 
on account of its dense covering with small spines, I have named 
L. dasyacanthus. I have in cultivation one of the largest speci- 
mens seen by Dr. Wislizenus, which is one foot high. In this 
neighbourhood, Opuntia Tuna, Mill., was seen for the first time, 
and this is perhaps the most northern limit of that extensively 
diffused species, as well as of Agave Americana, another common 
Mexican plant. Both were found in greater perfection near 
Chihuahua, and from there constantly down to Monterey and 
the mouth of the Rio Grande; the Opuntia appears to extend 
also high up in Texas. ~ : 
Together with these a Dasylirion, perhaps the same as the 
Texan species, was found here, and afterwards again near Saltillo. 
From El Paso to Chihuahua, the road lies in part through a 
dreadfully arid sandhill district, where a peculiar A/artynia was 
observed, and further on, through a lovely country, which, at 
that season, (August,) after the annual rains, was covered with a 
luxuriant vegetation. The elevation of the country is here 
between 4,000 and 5,000 feet above the gulf. 
