47 
comes near to S. multicaulis, Nutt., of the Rocky mountains, 
and S. Moginiana, DC. of Mexico; a new Bouvardia, which is 
remarkably distinct from all the other Mexican species of this 
genus by its smoothness; an Hchiveria perhaps identical with 
the Californian 7. cespitosa, DC.; several Gerania, which ap- 
pear to be undescribed, one of them with white flowers; an’ 
Eryngium, with the lowest leaves most elegantly pectinated, and 
the upper ones palmately divided; a Zinnia, intermediate 
between Zinnia multifiora and Z. elegans, and which last season 
grew finely near St. Louis from seeds picked from these speci- 
mens. Many other Composite have not yet been examined; a 
Centaurea may be found to be distinct from C. Americana, so 
far the only American species of that genus, which is so exten- 
sively diffused in the old world. 
Leaving aside several Dalee, Lupini, Gilie, a Gentiana, Buch- 
nera, Castilleja a number of Ladbiate, Gramineae, and many 
others, I will only mention a few more, which I had time to 
study more closely. First of all, the beautiful and delicate 
Fleuchera sanguinea, probably the most southern, and certainly 
the most ornamental, species of that genus. Next in beauty 
comes the bright-flowered Pentstemon coccineus ; Lobelia mucro- 
nata, with fine red, and JZ. pectinata, with blue flowers. 
Amongst the most curious plants collected here is also to be 
mentioned an Hriogonum with inflated clavate internodia and 
dark red flowers. Phaseolus bilobatus is another interesting 
lant. 
i In the following spring Dr. Wislizenus accompanied the 
Missouri volunteers, under Colonel Doniphan, from Chihuahua 
to Parras, Saltillo, Monterey, and Matamoras. _ 
Zealous as ever, he again made large collections on his tour, 
but his duties as a military surgeon occupied his time rather 
more than the naturalist 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 south- 
western limits of the valley of the Rio Grande. 
Before going into the detail I will only remark here, what a 
reference to the map and sections will more fully present, _ 
the country between Chihuahua and Parras has a general eleva- 
tion of from 4,060 to 5,000 feet; between Parras and Saltillo 
it rises from 5,000 to 6,000 feet, and thence it rapidly descends 
towards the lower Rio Grande. 
South of Chihuahua, a curious leafless Huphorbia was collec- 
ted, with tuberous roots and leafless stem, nevertheless apparently 
