109 [ 26 ] 
In the following spring Dr. Wislizenus accompanied the Missouri vol- 
unteers, under Colonel Doniphan, from Chihuahua to Parras, 
Monterey, and Matamoros. / 
Zealous as ever, he again made large collections on this tour, but his 
duties as a military surgeon occupied his time rather more than the nat- 
uralist should have desired. Nevertheless his collections are very full. 
Fortunately Dr. Gregg accompanied the same expedition, and also made 
rich collections in that almost unknown region, which we may consider 
as the southwestern limits of the valley of the Rio Grande. 
Before going into detail I will only remark here, what a reference to 
the map and sections will more fully present, that the country between 
Chihuahua and Parras has a general elevation of from 4,000 to 5,000 feet; 
between Parras and Saltillo it rises from 5,000 to 6,000 feet, and thenice it 
rapidly descends towards the lower Rio Grande. 
South of Chihuahua, a curious leafless Euphorbia was collected, with 
species, which has been confounded with it, to be entirely distinct. The 
_ description of the plant, (which died without producing flowers,) found 
in several works, as well as in the latest publication on Cactaceae, before. 
me, of Foerster, Leipzig, 1846, was made, as Prince Salm informed me, 
from specimens sent font Chihuahua by Mr. Potts; it entirely agrees 
with my specimen from the same region. Butthe description in Foers- 
ter’s work of the flower of a specimen in Cassel, flowering In 1843, (not 
on shorter petioles; some of the lower joints about 6 lives in diameter, 
the upper ones much less tumid; pedicells 1 to 3, lowest even 4 inches 
long; involucrum about 1 line long and wide, always 5 toothed, including 
25 to 30 deep red flowers; lobes about equal; nut olive green acuminate 
three winged. Singularly near EZ. inflatum, . and Frem., perhaps 
too near to be specifically separated; but apparently distinct by the hairy 
leaves and bracts, the furcate division of the stem, the large number of 
flowers in each involucrum, and perhaps their purple color, (not men- 
. Sp. 
foliolis adpresse pilosis reticulatis, lateralibus subsessilibus inaequaliter 
bilobatis, terminali petiolulato, lineari-oblongo; pedunculis folia longe 
Superantibus multifloris; culycis hirsuti lacinis subulatis tubum aequan- 
tibus ; leguminibus compressis, hirsutis, curvatis ; seminibus | 
Common about Cosihuiriachi, fowers in September. Resembles Ph. 
wus, T'. and Gr., but the brown-red flowers, and legumes much 
smaller; shape of the leaves very characteristic. Legume ¥ HI 
and 1 line wide, seed very small ; 
Lf ee ep 
