Each area within the dunes has something different to offer. Low dunes
near the picnic area have more vegetation than the tall dunes near
Highway 190.
Plants, visible from the top of many dunes, help the dunes remain here
by stabilizing the sand with their branches and roots. You will see
different plants, depending on whether you are in the tall or low dunes.
You may find them in a different sequence from that used in this
booklet. By looking for different shades of green, you should find each
of the major shrubs and trees that live in the dunes. Use the diagrams
and photos to help identify those you see. Let’s take a closer look to
learn how they survive and how they relate to the story of the dunes.
Can you find a low bush which appears to have no leaves? The stems are
jointed and succulent (juicy) and vary in color from yellowish to bright
green, depending on the season. Pickleweed (_Allenrolfea occidentalis_),
is often found on top of low mounds of sand. Do the stems look like tiny
pickles joined end-to-end? During summer months, tiny, inconspicuous,
yellow flowers may be seen at the joints. With a magnifying glass, you
may see the miniature leaves.
[Illustration: PICKLEWEED
(_Allenrolfea occidentalis_)]
By reducing leaf size, the plant minimizes surface through which water
can be lost. Green stems assume the task of photosynthesis, normally
done by leaves, providing food for the plant of this arid environment.
Although the sand does not often appear wet, pickleweed suggests water
is not far below the surface. It requires a wet soil and can grow in
very salty areas. Watch for pickleweed near Badwater also.
Find a different shrub, gently rub a leaf and smell it. Does it smell
faintly like fish? Look at the leaf you have just rubbed. Did the
surface dust rub off to reveal a deeper shade of green? Does it have
fleshy leaves? If so, you have found the inkweed (_Suaeda torryana_). If
your shrub has a less noticeable smell, and perhaps rubber-like texture,
and if you did not easily remove the white chalky coating from the light
gray green leaves, it is saltbush. If your shrub has numerous tiny
spines, be careful, you may have found a Russian thistle (_Salsola
kali_) or tumbleweed, as it is also called. They are not native to Death
Valley, but have become established in certain areas.
[Illustration: INKWEED
(_Suaeda torryana_)]
Inkweed’s young succulent leaves and seeds were used for food by local
Shoshoni Indians. Stems and leaves were processed to make a black dye.
You may notice tiny balls of seeds at the very ends of some branches.
The green flowers are very inconspicuous.
[Illustration: FOUR-WING SALTBUSH
(_Atriplex canescens_)]
Saltbush is light green and its dry, flat leaves are covered with salt.
Roots remove salts from the soil and water, then the salt is deposited
on the outer surface of the leaves. Consequently, the whitened leaf
surfaces reflect sunlight, thereby reducing temperature and water loss.
There are male and female saltbushes. You may want to search for seeds
or flowers. Seeds on female bushes have four tiny wings which give it
the name—four-wing saltbush (_Atriplex canescens_). Seeds were used as
food by Shoshoni Indians.
On your way into the dunes did you notice any other plants? If not,
watch for them as you return to your vehicle. Remember, the kinds of
plants vary depending on your location in the dunes. The clumps of grass
near the picnic tables are alkali sacaton (_Sporobolis airoides_).
Approaching the tall dunes you may have seen large plants with small,
shiny, smooth, dark green leaves—the creosote bush (_Larrea
tridentata_). It has small yellow flowers, usually observed in
springtime. Later, small, fuzzy, white balls containing seeds grow on
its branches. The larger green or brown, walnut shaped growths on the
branches are galls formed in response to an insect invader (midge). If
you missed creosote bushes in the dunes, watch for them along the
roadsides—they are common.
[Illustration: CREOSOTE BUSH
(_Larrea tridentata_)]
Although the sand dunes seem dry, there is an underground reservoir
providing moisture and nutrients for vegetation. The crusty mud playa
acts as a cap and reduces evaporation of the underground water supply.
Nearby, at Salt Creek, the same water flows on the surface as a stream
during the winter and spring.
[Illustration: MESQUITE
(_Prosopis glandulosa_)]
Most plants grow in the hollows between the dunes where they receive
some protection from the wind and can reach water more easily. Yet, the
mesquite tree (_Prosopis glandulosa_), probably the largest plant in
sight, is often on top of the dunes. By slowing the wind with its
branches, the mesquite causes sand to pile up in mounds beneath it.
Sometimes sand completely covers a part of the tree causing branches to
die. The sand then blows away, exposing those dead branches. Look for an
example which illustrates this sand movement. Mesquite trees have
thorns, so be careful. The mesquite tree loses its small, delicate
leaves during winter. Its deep root system, growing 50-60 ft. (16-20 m)
into the ground to reach fresh water, helps the tree survive. Some
plants, such as saltbush, pickleweed, and mesquite seem incompatible
because of different mineral and water requirements. However, these
plants are able to live near each other because their roots are drawing
moisture and nutrients from different levels of the soil. For example,
in a rain forest, where the roots have ample water, most plant growth is
above ground where competition is for sunlight. Whereas in a desert,
where sunlight is abundant, competition for water is more critical. The
root system of desert plants are highly developed, and each plant will
find the optimum level in the soil suitable for its growth.
[Illustration: _Mesquite tree: sand collector, food and shelter for
animals and Shoshoni._]
Be careful not to trample the roots as you explore the mound of sand
near the mesquite tree—you may collapse a burrow—remember, you and the
animals may be sharing the same shade.
Mesquite trees are also special in that they produce an edible and
nutritious fruit. In late spring, tiny, yellow flower spikes hang from
the branches. These develop into yellow bean pods by late summer. Many
different animals use the beans for food. Mesquite beans were also a
major food source for the Shoshoni.