Ес de = E E 2 UNITED STATES AND MEXICAN BOUNDARY. 
ae the occurrence of rains the open plans are лемі by a карый оЁ bright eae 
-` evanescent annuals, among the most conspicuous of which are-Vesicaria, Eschscholtzia Douglasit. 
=. A scanty growth of annual grama grass grows beneath the ever abundant Larrea, and the 
ES ; more alluvial portions of the tract are occupied by Obione canescens. In the deep cracks of the 
7 27 smooth washed surface Bowlesia tenera and some species of Hosackia are found. Near the 
25 : “immediate valley of the Gila we encounter species of Œnothera, Simsia, Gaillardia, and 
x a : Oligomeri is glaucescens.. 
шоог The valley of the Gila has many features. in common with that of the Rio Grande, and 
. :; among the botanical productions common to both valleys we notice Tessaria borealis and 
The trees bordering the stream are mostly 
>? 
ae mezquite, which latter forms dense “ chaparral. 
cotton wood and willow. 
VEGETATION OF THE RIO GRANDE, CANONS, AND THE CONNECTED BASINS, 
The flora of the caiions of the Rio Grande differs but little from that of the mountain ravines 
28 : ES have already alluded to. "We find stunted shrubs rooted in the crevices of the rocks or 
2 ` scattered along the broken summits. The abrupt walls, whether of limestone or of igneous 
E rock, afford favorable places for the growth of such plants as affect inaccessible localities. Here 
ss. we meet two species of the well characterized genus Laphamia, viz: L. dissecta and L. bisetosa ; 
E : also Perityle aglossa and L. Parryi, the pretty Eucnide lobata, Cowania ericifolia, and emoryi, a 
с new genus of the order Scrophulariacece, dedicated to Major Emory. 
In open places the vegetation peculiar to table lands makes its appearance. 
. In the more extensive basin of Presidio del Norte the flora partakes of the character of that 
cof Mexico, and more tropical forms prevail. We find here Kallstroemia grandiflora, Martynia 
Pl violacea, 1 M. arenaria, Talinopsis frutescens, Nicolettia Edwardsii, and several species of Boerhaavia. 
^ Cereus Greggii is mel common, and the delicious fruited Cereus stramineus grows in its greatest 
“perfection, 2 ; 
: . All the мыш and cañons within these limits Да а similar nt to the one just.. x: : 
T In de Chisos s basin a remarkable оон plant, allied to Scutellaria, was diseovered. This 
Dr. ‘Torrey has described as Salizaria, a new genus of the order Labiata. It has a straggling - i 
habit, and grows along the gravelly margins of dry water courses. The Sierra Carmel, upon E 
the summits of which we should expect to meet with many botanical novelties, was passed, in 
necessarily hurried march, in the month of November. Under these circumstances but little 
information could be obtained respecting its flora. Live oaks and the nut pine grew upon the 
higher ridges, and its upland plains and valleys were covered with luxuriant grama grass. The 
“beautiful Santa Rosa valley is marked by the most attractive scenery. Its broad and fertile 
plains, with copious streams, bordered by gigantic cypress, sycamore, and pecan trees, with a 
s back ground of high mountains, form a landscape upon which the traveller, wearied by the 
БЕ ‘monotony of the sterile table lands, gazes with the keenest enjoyment. 
ы From this point, on approaching the lower course of the Rio Grande, lying to the southwest, 
с хат із а sudden transition to the forms of зөрилрох, before alluded to ав characterizing this 
2 M arid and thorn beset district. ee 
