DESERT SHRUB VEGETATION, 
Figure 49.—A pure open stand of shadscale plants about 1 foot high. (Sagebrush.) One of the 
most extensive types of the northern desert shrub. The few associated plants contribute little to 
the general appearance. In growing condition or in dormant condition the plants are ash-gray in color, blend¬ 
ing with the desert soil. The branches are rigid and the individual plants tend to form low hummocks. 
This is the most important type of the southern part of the Great Basin, where the temperature is higher 
and the rainfall lower than on sagebrush land. The soil indicated by shadscale is usually shallow 
or heavy and strongly saline in the deeper layers, and is, consequently, not suitable for dry-farming. 
Lund, Utah. 
Figure 50.—Mats of salt sage with plants about 5 inches high. (Sagebrush.) The small, widely 
spaced mats blend with the desert soil and give a barren appearande. Next to the barren salt flats, this is 
the scantiest desert vegetation. Salt sage occurs on land from which the run-off is large, the moisture con¬ 
ditions being even more severe than on shadscale land. The rains penetrate usually only a few inches, 
and alkali is often found to the very surface. Near Grand Junction, Colo. 
Shadscale (fig. 49).—The shadscale ( Atriplex con- 
fertifolia) covers an extensive area in Utah and Ne¬ 
vada, and occurs less abundantly in Wyoming, Colo¬ 
rado, southern Idaho, Oregon, and eastern California. 
In relatively small isolated areas it pushes south into 
New Mexico, Arizona, and into the Mohave Desert of 
California. It usually lies below the sagebrush and 
just above the salt-desert shrub. Where ground water 
lies at a depth of several feet, greasewood often occurs 
as scattered widely spaced plants on land otherwise 
characterized by shadscale. This is one of the most 
common mixed types of the northern desert region. 
Shadscale also comes in contact with the short grass 
east of the mountains in Colorado and in New Mexico 
and Arizona. It probably covers more land in Nevada 
and Utah than does the sagebrush. The rainfall is less 
than over sage land and the heavy character of the soil 
much more conducive to high run-off. As compared 
with sagebrush land the moisture conditions are much 
more extreme. The root system is much shallower than 
that of the sagebrush, due to the more limited water 
supply. During periods of extreme drought this plant 
is often killed over large areas. Like the sagebrush, it 
is characterized by a practically pure stand. 
In contrast with the silvery foliage of the sage¬ 
brush, the shadscale is gray, and the whole land¬ 
scape presents an appearance of extreme monotony. 
In autumn the plants change to a reddish-brown 
color, and during the favorable years a heavy crop of 
seed is produced. The plants are hemispherical and 
usually scattered evenly over the surface of the soil, 
but never produce a dense stand. Between the plants 
the soil usually is bare. The plants vary in height 
from 6 inches to 2 feet. If the soil is especially poor 
and the rainfall unusually light, the plants may be only 
a few inches high. On relatively good soil the plants 
may be 2 feet high. This type indicates harmful 
amounts of alkali at a depth of I or 2 feet or a soil 
poorly supplied with water with a hardpan at the same 
depth. This land is unsuitable for dry farming, but 
where the soil is not too shallow it can be made produc¬ 
tive under a proper system of irrigation. 
Winter fat .—Within the zone occupied by the shadscale. 
occurring on similar soil and under similar climatic conditions, 
are a number of minor groups. Winter fat (Eurotia lanata) 
covers hundreds of square miles in Nevada and Utah. The 
plants are usually small, almost white in color, and rather 
widely spaced. Areas can be detected at great distances be¬ 
cause of the uniform white or light-gray color, which at a 
distance appears like snow. The plants are shallow rooted 
and often grazed almost to the ground. This plant occupies 
land almost as heavy as that covered by shadscale, but which 
contains only a small amount of alkali. It is one of the most 
valuable forage plants of the Great Basin region, and is 
especially highly prized by sheepmen. Although the pure areas 
are most extensive in Nevada and Utah, it is a common plant 
over a much wider range and contributes much to the forage 
resources of the intermountain region. Agriculturally this is 
similar to the shadscale land. 
Sop sage .—Under conditions intermediate between 
shadscale and sagebrush large areas occur which are 
occupied by hop sage ( Grayia spinosa) . During the 
winter this shrub presents very much the appearance of 
sagebrush, with which it is often mixed. It is found 
most commonly in the northern portion of the area. 
Bud sage .—Bud sage ( Artemisia spinescens ) is es¬ 
pecially prominent in Nevada and occurs throughout 
Utah, Colorado, and the Northwest. It occupies rather 
limited areas and does not differ markedly from the 
shadscale in its distribution. It is especially valued by 
sheepmen. Sheep which, during the winter, have 
grazed on winter fat are first moved to areas of bud 
sage because the young shoots of this plant produce 
excellent forage and constitute the principal feed in the 
early spring. 
Salt sage (fig. 50).—Salt sage ( Atriplex corrugata , 
A. nuttallii , and allied species) ranges somewhat far¬ 
ther north than shadscale and occupies especially large 
areas in Wyoming, Colorado, and Utah. It occurs in 
small areas in Montana, Idaho, Oregon, and California. 
In Montana, Wyoming, and Colorado it pushes out 
into the short-grass areas, but never becomes dominant 
over large areas east of the mountains. Great ex¬ 
panses are covered with this ash-colored low-growing 
plant, which forms large mats and is seldom more than 
a few inches high. The total amount of growth pro¬ 
duced on this type is small, and the landscape presents 
to the eye a relatively larger amount of bare ground 
from which the plant is not readily distinguished at a 
distance. It occurs usually on a soil from which the 
run-off is comparatively great and which accordingly 
supplies only a small amount of water for plant growth. 
The moisture conditions are even more extreme than on 
shadscale land. Soil moisture is confined to within a 
few inches of the surface, and only a relatively small 
total moisture supply is available for plant growth. 
Plant growth occurs largely in early spring, and the 
plants pass most of the summer season in a rest condi¬ 
tion. This type is found usually in regions having less 
than 10 inches of rainfall and a high evaporation rate. 
The soil usually contains harmful amounts of alkali to 
the very surface. Land under this type of vegetation 
is not' adapted to dry farming, but when the proper 
system of irrigation is applied it may be leached so as 
to become good agricultural or orchard land. 
White sage. —Land similar to that occupied by salt 
sage is sometimes dominated by white sage ( Kochia 
americana vestita). These areas are found in por¬ 
tions of Utah and Nevada, and are not extensive. In 
appearance they can be distinguished with difficulty 
from winter-fat areas. The two species are of about 
equal height as a rule, but the white sage is not as 
white as is the winter fat. White sage spreads by 
underground rootstocks, the plants are evenly dis¬ 
tributed, the spaces between the plants being either 
bare or occupied usually by a small grass (Poa sand- 
bergii). As a rule the surface of the soil is very 
light in color and a decidedly heavy loam in charac¬ 
ter. Alkali, while not noticeable at the surface, is 
abundant at a depth of 10 inches or 1 foot, and dur¬ 
ing most of the year the soil at a depth of 1 foot 
is moist, owing to the high alkali content, which in¬ 
hibits the production of plant roots in this zone. Be¬ 
cause of its compact character and high alkali content, 
land characterized by this plant is unsuited for irri¬ 
gation agriculture, unless the alkali can be leached to 
some extent. During years of unusually well distrib¬ 
uted rainfall land of this type will produce crops under 
dry-land culture, but it should not be regarded as pro¬ 
ductive dry-farm land. White sage is only grazed to a 
small extent, and the grazing value of this land is due 
to the associated grasses. 
CREOSOTE BUSH (SOUTHERN DESERT SHRUB). 
This type presents a much more varied appearance 
than the sagebrush desert. (Figs. 51 to 56.) The most 
important plants, creosote bush and mesquite, are 
shrubby, or sometimes the latter is treelike and con¬ 
tinues growing through long periods of drought, hav¬ 
ing a much longer growing period than sagebrush. 
Yuccas, cacti, and spiny desert shrubs are prominent 
in many parts of this desert. 
This desert occupies a comparatively narrow belt 
across the southern portion of the United States from 
the Pacific Ocean to the Gulf of Mexico. It does not 
occur to any extent north of the thirty-seventh paral¬ 
lel. Along the Virgin River in southern Utah this 
type reaches its most northerly limit. It is confined 
almost entirely to the Mohave Desert, the valleys of the 
Colorado, the Gila, the Rio Grande, and the Pecos. A 
small area of inland valley land in southern California, 
west of the main range, has also been included. The 
climatic conditions in this desert are more extreme 
than in any other portion of the country. The rain¬ 
fall varies from about 2 to 20 inches, and the greater 
portion of the area receives less than 15 inches of rain. 
Over most of the area west of the Colorado River no 
rain falls during the hot summer months, the great por¬ 
tion occurring during the winter months. In other sec¬ 
tions, on the contrary, especially those lying in Texas 
and New Mexico and the southeastern portion of Ari¬ 
zona, the rainfall during the summer is greater than that 
during the winter. Here grasses become relatively 
abundant. The temperature over all this area is high, 
often reaching 100° to 125° F. Over much of the area 
it rarely falls below 20° to 25° F., and the frost-free 
period usually ranges from 180 to 270 days. Because 
of the intense heat and the very rapid evaporation the 
conditions in portions of this area are more extreme 
for plant growth than in the northern desert shrub, 
although in many parts the wide spacing of the plants 
and the pervious nature of the soil combine to supply 
a quantity of available moisture sufficient to enable the 
desert shrubs to continue growing through extremely 
long periods of drought, in some cases lasting a year 
or more. 
This desert is not sharply separated from the 
chaparral zone, into which it merges. On both the 
coast and the desert side of the mountains of Califor¬ 
nia the great Adenostoma area of the chaparral zone 
lies just above areas of wild buckwheat or Encelia 
and California sagebrush, and these types, here classi¬ 
fied with the southern desert, could with reason be 
placed with the chaparral. In the Mohave basin and 
in other portions of the southern desert the yucca- 
cactus type merges into the juniper. Shadscale pushes 
down into this desert from the north, and chamiso is 
common to both deserts, but is best developed in the 
southern desert. The line of demarcation between the 
southern desert shrub and the desert grassland is even 
more difficult to draw. Over great stretches of grass¬ 
land are scattered shrubs or other large southern desert 
plants. On the map, areas dominated by shrubs have 
been placed in the southern desert, while areas which 
show only scattered shrubs over the grass cover have 
been mapped as desert grassland. 
This shrub desert lies for the most part in a rela¬ 
tively frost-free area, and wherever water is available 
