Vegetation of the Sotol Country. 
105 
Miles west of 
the Sabine. 
Elevation in 
feet. 
Approximate 
annual rain- 
fall in inches. 
Physiography 
and Soils. 
Character of the 
Vegetation. 
Langtry 
550 
1321 
ca. 15 
Rio Grande canyon 
and branches; 
high gracefully 
sloping hills, wide 
draws, broad di- 
vides, coarser or 
finer limestone 
derbis every- 
where. 
Typical sotol country; larg- 
areas of lechuguilla; chape 
arral; Oovillaea, Flouren- 
sia, Koeberlinia, Micro 
rhamnus, Ephedra; many 
species of cacti; Yucca, 
Hesperaloe, Selaginella; 
bunch grasses. 
Haymond 
668 
3883 
ca. 15 
High, level or gent- 
ly rolling plateau 
with isolated 
mountains ; deep 
covering of fine, 
loose wind - swept 
soils; coarser 
debris on moun- 
tain slopes. 
Western border of main sotol 
belt ; edge of grassy plateau ; 
cylindrical Opuntias com- 
mon. 
Marfa 
743 
4692 
ca. 18 
Level plateau with 
fine loose soils; 
isolated mountain 
masses. 
Typical short grass country 
like staked plains; rich in 
prairie annuals; flat areas 
with Yucca radiosa and 
Koeberlinia. 
El Paso 
939 
3713 
ca. 9 
Rio Grande valley; 
high arid gravelly 
mesas. 
On mesas, Oovillaea, Sarco- 
batus, Fouquiera. Croton; 
many cacti, shrubby com- 
posites, scattered grasses, 
desert vegetation. 
SUMMARY OF TRANSITION PHENOMENA. 
1. From heavy rainfall and humid atmosphere to almost rain- 
less desert. 
2. Gradual disappearance of Austro-riparian species and sub- 
stitution of Lower Sonoran. 
3. At the east, vegetation makes dense earth cover; at the west, 
it is very open, and the earth everywhere exposed. 
4. Gradual dwarfing of woody vegetation. 
5. Western limit of cultural zones indicated by the character 
of the native vegetation. 
6. Eastern vegetation broad leafed, foliaceous; westward, veg- 
etation non foliaceous, leaves variously modified or wanting. 
7. Eastward, the contrast between summer and winter phases 
is strong; westward, the differences are much less noticeable in the 
dominant vegetation. 
