50 BOTANY OF DR. A. WISLIZENUS’S EXPEDITION 
edible succulent fruit with very thick seeds. Fortunately, the seeds collected by [102 (18)] 
Dr. Wislizenus arrived here in the best condition, and some have already germinated, so 
that we may hope to raise some of these species. Yucca aloéfolia, of the Southern United States 
and Mexico, is said also to bear an edible fruit, but has serrulate leaves. We have therefore different 
species of Yucca with edible fruits, which may constitute a peculiar section in this genus. 
The soil appeared to be too fertile here for the production of Cactc ; and, with the exception of 
some Opuntia, the only species collected between Paso and Chihuahua — about one hundred miles 
south of the former place — was Cereus Greggii8 which was peculiarly interesting, as it is probably 
the most northern form of Cereus proper. The specimens sent for cultivation by Dr. Wislizenus 
were unfortunately dead when they arrived here, and neither flower nor fruit had been obtained; 
but Dr. Gregg has collected the same species near Cadena, south of Chihuahua, in flower, from 
which I completed the description. I could not have given it a more 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 Myr. Potts, of Chihuahua; but his speci- 
mens also did not live; they were very remarkable for having a thick turnip-shaped root. Neither 
Dr. Wislizenus nor Dr. Gregg having paid attention to the root, I am unable to say whether their 
specimens agreed with those of Mr. Potts in this particular. 
Dr. Wislizenus was forced to go from Chihuahua westward to Cosihuiriachi. However preju- 
dicial this involuntary interruption of his journey may have been to the primary objects of his 
expedition, it appears that he could not have selected a more favorable 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 everything collected there appears to be new ! 
Among 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 flexilis, which I name 
P. strobiformis.* Its size and growth, its foliage, as well as the shape of the cones, [103 (19)] 
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. 
%8 CerEus GREGGII, n. sp.: erectus, ramosus, pentagonus ; areolis distantibus oblongis, nigro-tomentosis; aculeis 
nigris, brevissimis, e basi incrassata subulatis, acutissimis, 6-9 radialibus subrecurvis, infimis longioribus, centrali 
singulo deflexo minuto; tubo floris elongato, areolis 60-80 cinereo-tomentosis setas 6-12 nigricantes s. apice albidas 
gerentibus stipato ; sepalis interioribus 15-20 et petalis 15-20 lanceolatis, acuminatis, integris, 
North and south of Chihuahua; flowers April and May. Stem 1 to 2 feet high, about 6 lines in diameter ; 
spines 4 to 1 line long, extremely sharp; flower about 6 inches long and 2 inches in diameter; bristles of the tube 
14 to 3 lines long ; interior sepals reddish green, petals pale purple. 
%4 PINUS STROBIFORMIS, n. sp.: squamis turionum ovatis acuminatis ; vaginis laxis, patulis, deciduis; foliis 
quinis filiformibus, supra albo-lineatis, acute carinatis, subtus convexis, margine tenuissime serrulatis; stro ilis 
cylindricis, elongatis, squamis obtusis inermibus, demum recurvis, 
Highest peaks about Cosihuiriachi. The largest pine in this region 100 to 130 feet high. Sheaths 6 lines long, 
very deciduous ; leaves 2 to 34, mostly 3 inches long; cone about 10 inches in length, very resinous. This species 
forms, with Pinus Strobus and Pinus flexilis, a peculiar section, distinguished by their five leaves and their cylindric 
pendulous squarrose cones. The leaves of P. Strobus are the most slender, concave on the back, and strongly serrate ; 
those of P. strobiformis are somewhat more rigid, convex on the back, and slightly serrate ; those of P. flewilis are still 
more rigid, convex on the back, and entire. 
% PINUS MACROPHYLLA, n. sp.: squamis turionum longe acuminatis, fimbriato laceris, squarrosis, persistentibus; 
vaginis elongatis, adpressis, laceris ; foliis ad apicem ramulorum congestis ternis, quaternis (rarius quinis) longissims, 
