PHOENIX, ARIZ. -- There are two secrets hidden beneath the crust of this dry, brown and hot cityscape. One is that the wild things begin where the shopping centers end. The other is that among the cacti and scrub that look like a set for "Death Valley Days" are hundreds of edible plants.

Wild plants have sustained American Indians in the desert for centuries, but urban sprawl, modern agriculture and processed foods have largely displaced them. State laws prohibit gathering of several native plants without a permit. And just like astro-turf, cacti and "natural" desert landscapes have to be installed.

Enter Ruth Greenhouse, the agricultural equivalent to the Save the Whales movement. Greenhouse, a dietitian, ethnobotany enthusiast and research associate at the Desert Botanical Gardens, wants to save the desert plants -- or at least make people appreciate them. Greenhouse leads workshops on traditional uses of desert foods, organizes harvesting treks on the museum's grounds and is working on a new exhibit trail called "Plants and People of the Sonoran Desert" that will show -- according to a museum pamphlet -- "the real but often misunderstood richness" of the desert terrain.

There is a "whole technology of how to survive in the desert," says Greenhouse, sitting in the museum's office, surrounded by the earth tones of wild things in glass jars. Desert gatherers had to know when the plants were in season, where to find them, how to store them and how to process them, Greenhouse explains. And southwestern Indians used plants to the fullest capacity, dissecting them not only into their edible components, but also for use as medicines and in construction and storage.

One of the wild plant staples for the Indians of the lower Colorado River and central and southern Arizona was mesquite, says Greenhouse, offering a visitor a taste of a mesquite bean pod, the sweet, dried legume of the mesquite tree. The indigenous peoples would grind the beans into flour to make gruels and porridges, or boil the beans to make mesquite tea. (Greenhouse's mesquite workshop information sheet lists microwave mesquite bread and mesquite cookie crisps as two updated recipes.)

The "kiwi" or "caviar of the desert" is what the fruit of the saguaro cactus is often called, says Greenhouse, slicing the green, avocado-shaped fruit to reveal a luscious red interior. (The saguaro is the pronged-shaped cactus that dots the backdrop of Western movies.) The Pima and Papago tribes simmered the juice into syrups or wine, or ground the seeds into flour. The syrup resembles molasses in its consistency and taste; the fruit tastes similar to New Zealand's kiwi.

Saguaro fruit -- which grow on the tips of the towering saguaro -- were harvested by long T-shaped rods made from the inner ribs of the cacti. After the cacti died, and their fleshy exteriors rotted, the American Indians would dislodge the callous boot-shaped cavities that remained in the woody ribs. Formed by a lifetime of woodpeckers' work, these containers were used for storing food.

In the kitchen cabinets at the museum office are modern-day storage containers: vials and jars filled with twisted dried beans, unfamilar seeds and strange liquids -- tepary beans, ironwood seeds, mesquite tree sap. In the refrigerator, a jar of prickly pear cactus jelly shares shelf space with packages of cream cheese and containers of yogurt.

The indigenous Indian diet was nutritionally balanced, explains Greenhouse. Cultivated corn, beans and squash, plus wild foods such as mesquite pods provided carbohydrates; protein needs were met by combination bean and corn dishes, seeds from wild grasses and dried meats; calcium was consumed in cholla buds and wild greens; and iron came, unexpectedly, from plant ashes used in cooking, writes Greenhouse in the Desert Botanical Gardens quarterly, called Agave. (The hearts and immature flower stalks of the agave, a desert plant, were also eaten by the Indians. Several species of agave are pollinated by long-nosed bats. The fermented, distilled juice of the plant is tequila.)

While the food gatherers' diet was historically high in fiber and low in fat, unfortunately today many southwestern Indians have astronomically high incidences of diabetes, obesity and other nutrition-related diseases. The demise of a diet based on native plants has been "tentatively related" to the upswing in the incidence of some of these diseases, writes Gary Paul Nabhan, assistant director for research for the Desert Botanical Gardens and author of "Gathering the Desert" (University of Arizona Press, $14.95).

Consequently, to improve nutrition and preserve cultural traditions, consumption of native foods has recently been encouraged by the Tohono O'Odham (formerly the Papago) tribe, says Greenhouse. This "revival" has included teaching tribal children how to identify and prepare various wild edible plants, she adds.

Under a 114-degree sun that absorbs the moisture from your mouth like a suction cup, Greenhouse leads a tour of the desert trail, funded by the National Endowment for the Humanities, which will be completed in November.

The exhibit will be divided into several plant communities, each demonstrating a different melding of plants with anthropology, history and gastronomy. The desert foothills section is already outfitted with a forest of saguaro cacti and a community of cholla cacti (the Indians used to roast the buds in underground pits and dry them).

A water truck pulls up to the desert stream area, where it empties its gallons into the artificial pond. This lush area will house cottonwood and cattail plants, explains Greenhouse. There are also plans to construct an irrigated garden of edible plants such as purslane, lambs-quarter and pigweed.

Further along the trail is the mesquite bosque, a forest of weedy-looking shrubs. While every steakhouse owner east of Topeka might see this as a charcoal warehouse, the bosque actually will demonstrate how the plant has been crucial for thousands of years not only for fuel, but for food, paint, construction material, medicine and cosmetics. (Because of the lowering of groundwater tables, dense mesquite bosques no longer exist in the Sonoran desert.)

Final components of the trail include an agave-roasting pit and a semi-desert grassland with prickly pear cacti and yucca.

While wild things from the Sonoran desert don't regularly show up in Washington supermarkets, here are some recipes from a cookbook available at the Desert Botanical Gardens that combine foods brought by Spanish settlers with those cultivated by the Indians of the Southwest.

THREE-BEAN SALAD WITH CHILE DRESSING (6 servings)

1 cup red kidney beans

1 cup pinto beans

1 cup chickpeas

1/2 cup finely chopped onion or scallions

2 tablespoons finely chopped parsley

1 small green pepper, chopped

4-ounce can diced green chilies

FOR THE CHILE DRESSING:

1/2 cup olive oil

1/4 cup red wine vinegar

1 clove garlic, finely chopped

Salt to taste

3/4 teaspoon each oregano and chile powder

Generous pinch ground cumin and hot pepper sauce

In a medium bowl, combine beans, onion, parsley, green pepper and chilies. To make chile dressing, combine all ingredients in a covered jar and shake well. Pour enough chile dressing over mixture to coat ingredients. Stir. Refrigerate unused dressing. Cover and chill salad at least 4 hours.

CORN CUSTARD (4 servings)

Butter for greasing baking dish

1 cup milk

1 teaspoon baking powder

1/2 teaspoon salt

Dash cayenne pepper

1 tablespoon sugar

1 clove garlic, finely chopped

3 eggs

3/4 cup cooked corn

1/2 cup shredded longhorn cheese

Butter a 1-quart baking dish. In a medium bowl, whisk milk, baking powder, salt, cayenne, sugar, garlic and eggs together. Stir in corn. Pour mixture into baking dish and bake 30 minutes at 350-degrees. Bake 10 to 20 minutes longer, or until a knife inserted near center comes out clean.

CHICKEN IN PUMPKIN SEED SAUCE (4 servings)

1/2 cup unsalted pumpkin seeds

1/4 cup blanched almonds

1/2 teaspoon cumin seeds

1/4 cup chopped onion

1 clove garlic, finely chopped

4-ounce can diced green chilies

1/2 cup chopped parsley or 1/4 cup chopped cilantro leaves

2 cups chicken broth

1 tablespoon lemon juice

4 large chicken breast halves, skinned and boned

Salt and freshly ground pepper

2 tablespoons vegetable oil

In a large skillet, toast pumpkin seeds, almonds and cumin seeds over low heat, shaking pan, until almonds are golden brown. In a blender or food processor, grind toasted mixture. Add onion, garlic, chilies, parsley and 1 cup broth. Blend until smooth. Pour mixture into medium saucepan. Stir in remaining broth and lemon juice. Bring to a boil, reduce heat and simmer, uncovered, about 15 minutes.

Meanwhile, season chicken with salt and pepper. In a large skillet, heat oil over medium-high heat. Saute' chicken until browned. Reduce heat to low, pour pumpkin seed sauce over chicken and simmer for 15 minutes or until chicken is tender and no longer pink and sauce is thick.

TEQUILA SAUCE (Makes about 2 cups)

4 egg yolks

1/4 cup sugar

1/8 teaspoon salt

1 3/4 cups hot milk

1 teaspoon vanilla

1 to 2 tablespoons tequila

In a medium saucepan, mix together egg yolks, sugar and salt. Stir in hot milk. Cook over medium heat, stirring constantly for 8 to 9 minutes, or until thickened, being careful that it does not boil. Stir in vanilla. Refrigerate sauce until completely chilled. Before serving, stir in tequila. Serve over fresh fruit or ice cream.

All recipes adapted from "Recipes From Arizona With Love," by Ferol Smith Golden and Lisa Golden (New Boundary Design, Inc., $8.95)