4.0 
and the northern parts of Mexico, where Cere? proper are very 
rare. They extend even farther north than the Hchinocacti, 
but appear to be excluded from the old limits of the United 
States, where the Cactus family is represented only by some 
Opuntia and Mammillarie. ‘The southern limits of the Lchz- 
nocerei are unknown to me, but I doubt whether they extend 
far in that direction; the nearly-related Hchinopsides, on the 
contrary, appear to be exclusively inhabitants of South America, 
especially the La Plata countries. 
As I am speaking of the geographical distribution of the 
Cactacee, I may as well add here that Mammillarie were found 
throughout the whole extent of Dr. Wislizenus’s tour, and that 
~ at least four species occur in Texas. chinocacti were observed 
only south of Santa Fé, and from there to Matamoros, but none 
on the highest mountains, which were occupied by Opuntia, 
Mammillaria, and Echinocerei; two LEchinocacti have been 
found in Texas. Only two species’of true Cerez were seen; one 
of a peculiar type about Chihuahua, and another near the mouth 
of the Rio Grande, which does not appear to differ from the 
wide-spread C. variabilis, Pfeiff. Opuntia elliptice, as well as 
cylindracee@, were observed from New Mexico to Matamoros, 
and species of both are also found in Texas. Melocacti, Phyl- 
locacti, and other genera of Cactacee, not mentioned above, 
were not met with. 
The notes and collections of Dr. Wislizenus confirm the 
opinion of that acute observer and succesful cultivator of Cactacee, 
Prince Salm-Dyck, viz: that most species of this family have a 
very limited geographical range, the most striking exception 
being those belonging to the genus Opuntia. 
On the same day two other species of Echinocereus were found 
in pine timber, both with beautiful deep red flowers. 
We shall have occasion to speak of others hereafter. 
After leaving Santa Fé, Dr. Wislizenus directed his course 
southward along the Rio Grande. The country was partly 
mountainous and rocky ; partly, and principally along the river, 
sandy; on an average between 4,000 and 5,000 feet above the 
ocean. Here we find again some of the plants of the plains and 
of Texas, as Polanisia trachysperma, T. and G.; Hoffmanseggia 
Jamesii, T. and G. An interesting Prosopis with screw-shaped 
legumes nearly allied to P. odorata, Torr. and Frem., of Cali- 
fornia, was the first shrubby mimoseous plant observed during 
the journey, a tribe which hereafter becomes more and more 
abundant ; Mentzelia sp. Cosmidium gracile, Eustoma, Helio- 
tropium currasavicum, .Maurandia antirrhiniflora, a° beautiful 
a : idle tbe gs é rs A j YY72, 
