Ad 
appropiate name than that of the zealous and intelligent explorer 
of those far off regions. I learn from Prince Salm-Dyck that a 
Cereus, probably the same species, was sent to England by 
Mr. Potts, of Chihuahua, but his specimens also did not live ; 
they were very remarkable for having a thick turnip-shaped root. 
Neither Dr. W. nor Dr. G. having paid attention to the root, I 
am unable to say whether their specimens ‘agree with those of 
Mr. Potts in this particular. 
Dr. Wislizenus was forced to go from Chihuahua westward to 
Cosihuiriachi. However prejudicial this involutary interruption 
of his journey may have been to the primary objects of his expe- 
dition, it appears that he could not have selected a more favourable 
field for botanical researches. Amongst the porphyry mountains 
of Cosihuiriachi and Llanos, which vary from 6,000 to 8,000 
feet in height, and their deep chasm-like valleys, a great many 
undescribed species of plants were found ; in fact almost every- 
thing collected there appears to be new! 
Amongst the trees, I mention three species of pines, entirely 
different from those found farther north, but perhaps identical 
with some species from the Pacific coast. ‘The most magnificent 
of these three is a species nearly related to Pinus strobus and 
Pinus flewilis, which | name P. strobiformis. Its size and growth, 
its foliage, as well as the shape of the cones, resemble the common 
white pine of the north, but the cones are two or three times as 
large, not to speak of the other differences. It only grows on the 
highest mountains of this region, of about 8,000 feet elevation, 
and attains the height of 100 to 130 feet. 
Pinus macrophylla, another inhabitant of the higher mountains 
of Chihuahua, is more common than the last ; like it, it closely 
resembles a well-known species of the United States, P. australis, 
from which it differs by its short cones, which have on each scale 
a mammillary recurved tubercle, and by having the leaves not 
only in threes, but also in fours and even in fives. It may be near 
P. occidentalis of the interior of Mexico, but that has regularly 
five leaves in each sheath. 
P. Chihuahuana is the common pine of Cosihuiriachi and the 
mountains of Chihuahua, in general at an elevation of about 
7,000 feet. It grows only thirty to fifty feet high, and resembles 
somewhat P. variabilis, though sufficiently distinct. Dr. Wisli- 
zenus was unable to obtain specimens of a fourth pine, which is 
said to grow on the still higher mountains to the west, near 
Jesus-Maria, bearing cones fifteen or eighteen inches in length. 
On the highest peaks in this region a species of Aréutus was 
found, which the inhabitants call J/afronia; it is a small tree 
