Sand dunes story

by Donna P. Bessken

WHAT PLANTS LIVE HERE?

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.

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.

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.

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.

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.

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.

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.