DESERT REGIONS OF NORTH AMERICA. 0) 
The more xerophytic chaparral species are in evidence here; e. g., 
Leucophyllum texanum, Muicrorhamnus ertcoides, Karwinskia humboldti- 
ana, Celtis pallida, Keberlinia spinosa, Acacia constricta, A. berlandiert 
(the huajilla), Leucena retusa (also, of course, the mesquite), Acacia 
amentacea and wrightit, and Mimosa fragrans (of farther east); occasional 
specimens of Mexican greasewood (Covillea tridentata), Krameria can- 
escens and ramosissima, Yucca treculeana, etc. 
Del Rio is 486 miles west of Orange, at an elevation of 956 feet, and 
although but a short distance from Spofford has a rainfall markedly less, 
the annual amount being on an average but 20 inches. This place lies 
in the alluvial valley of the Rio Grande and near the rough margin of the 
Edwards Plateau. Ridges with coarse limestone fragments and flats 
with calcareous clay and alluvial soils are included. Near here begins 
the arid, rocky, débris-covered country, to be included in the Chihuahuan 
Desert, which becomes emphasized a short distance to the westward, 
between Devil’s River and the Pecos, where sotol, ocotillo, lechuguilla, 
and cacti begin to predominate. 
The region shows areas of short open chaparral, with broken stretches 
of grass-land, or rather areas bearing bunchy grasses, while huajilla, 
Leucophyllum, Parkinsonia texana, and various species of Opuntia are 
abundant. 
Langtry is 550 miles west of Orange, at an elevation of 1,321 feet, and 
has an annual precipitation of but 15 inches. It lies near the canyon of 
the Rio Grande, the surrounding country including many of its branches, 
as well as high, gracefully sloping hills, wide draws, and broad divides, 
with coarse and fine débris of limestone everywhere. This is the typical 
sotol region, and the sotol (Dasylirion texanum) abounds on the broad 
divides, while the lechuguilla (Agave lechuguilla) occurs in abundance on 
the hilltops and slopes. Dwarf chaparral shrubs, Covillea, Flourensia cer- 
nua, Microrhamnus ericoides, Parosela formosa, Ephedra antisyphilitica, 
Jatropha spathulata, Acacia constricta and A. greggu, Krameria, Lycium, 
Mortonia, Fouquieria splendens,and the following cactiare found: Echino- 
cereus cespitosus, E. dasyacanthus, E. paucispinus, E. longispinus, Opuntia 
arborescens, O. arenaria, O. engelmannt, O. leptocaulis, Artocarpus fissur- 
atus, Echinocactus brevthamatus, E. horizontalonius, E. longithamatus, E. 
setispinus, E. texensis, Lophophora williamsu, Cactus contmamma, C. hey- 
deri, C. micromerts, C. pectinatus, C. pustllus, C. scolymoides, C. vivi- 
parus, C. dubius, and Cereus greggi. 
Haymond is 668 miles west from Orange, at an elevation of 3,883 feet, 
and has an annual precipitation of about 15 inches. The region here is 
a high, gently rolling plateau, bearing isolated mountains. The soil is 
fine, deep, and the surface of the ground is windswept. This marks the 
western border of the sotol region and the edge of a grass-covered area, 
the cylindrical opuntias being abundant. 
