For two hours, the group stumbled over dinner: dried Jack in the Pulpit root, which tastes similar to cocoa; wild carrots (otherwise known as Queen Anne's lace); day lily soup from lily tubers and fresh blossoms; cattails, which can be turned into porridge; liquid popcorn; and wild potato soup.

"If it smells like an onion, it is one," Jim Johnson said as he grabbed some wild onions growing along the path. "Leeks, wild garlic-they're all from the same family. Try some in a tossed salad."

Johnson was taking 30 people through the woods of the Avenel farm in Potomac on a recent Sunday afternoon. The leader of the edible botany walk, a biology teacher from Annandale High School, had created a banquet composed of wild foods for the Fairfax County Park Authority.

Seven years ago he became hooked on wild food on a similar outing, and since then he has created three "nature's banquets" with his own recipes. Some favorites are Venison Wellington, Snake a la King and Fish with Ants; but Johnson also had some pedestrian advice.

Tea can be made from fresh or dried plants such as heal-all or goldenrod. But don't use wilted ones, he explained: Most plants go through a chemical change in the process of drying that makes them poisonous.

Johnson picked each edible plant as he passed and asked the group to taste them. People would nibble, tentatively at first and then with more gusto.

The best smell was the sassafras root resembling ginger, and the best taste was the sassafras leaf. Some people balked at this delicious edible until Johnson estimated that the quantities of sassafras tea needed to cause cancer in humans are 8 gallons a day for 20 years. With that, the group sniffed and nibbled contentedly.

From dandelions: Coffee drinkers can try roasting the roots, and pancakes can be made from pancake batter, the yellow blossoms and water.

For salad, Johnson recommended green-briar leaves, sour grass, purslane tips, cattail shoots with red buds, and dandelion blossoms and violets for color. Or wine, jam or jelly can be made from them.

Poke weed-found under dry timber-can be boiled in one or two changes of water and then fried with pork. Johnson recommended removing the shiny green leaves with tinges of red and cooking the thick green stalks to make a poor-man's asparagus, or cooking the leaves for a poke weed souffle. As he explained, one eager group member dug up the roots with a trowel to transplant them to his own garden. "Don't touch that root with your hands," cautioned Johnson. "Its poisonous."

Silver maple keels, the green seeds that children call helicopters or pug noses, can be boiled in a few changes of water-their taste is similar to that of string beans.

The more accustomed the group members became to the wild, the more edible plants they gathered. Finally Johnson had to caution them to take only one-third of whatever was available-some of the plants like Jack in the Pulpit are becoming rare species because too many people have been picking them.

When Johnson pointed out the all-too-familiar posion ivy, people close to him jumped back. Some had mistakenly thought that Virginia Creeper, a five-leafed palmated, was the poisonous three-leafed plant. According to Johnson, nature always provides an antidote to poisonous or undesirable plants. Poison ivy's natural remedy, for example, is the common jewel weed, or tough-me-not.

Johnson explained that 80 percent of all edible plants, providing most of the nutrients needed in the human body, can be found at the forest's edge, because in the forest there is too little sunlight to produce leafy material. But he warned that one must stay at least 20 feet from the roadside because of the gasoline lead contained in the leaves.

All too soon the tour ended with a glass of two-year-old redbud wine. One more edible botany walk is scheduled this Sunday from 1 to 3 p.m. Call the Smithsonian Associates, 381-5157 for more information.

Here are some of Johnson's edible botany recipes.

DAY LILY SOUP

(4 to 6 servings) 1 cup day lily tubers 1 small onion, diced 2 tablespoons butter 1 cup dried or fresh day lily blossoms 1/2 cup milk 2 cups Jerusalem artichoke roots 1 cup canned condensed consomme Salt and pepper to taste

Peel and slice day lily tubers and combine with onion.Saute in butter until tender.

Add remaining ingredients, simmer, covered for 20 minutes. Adjust seasoning. Serve hot or cold.

WILD ONION SOUP

(4 servings) 2 cups chopped wild or regular onions 2 cups water 1 teaspoons salt 1 beef bouillon cube 1 tablespoon butter Croutons

Simmer all ingredients covered for 1 hour. Strain and serve with butter and croutons.

TOSSED SALAD WITH WATERCRESS DRESSING 1 part-greenbriar leaves (young and tender) 1 part watercress 1 part chopped onion tops 1 part sour grass (oxalis) 1 part purslane tips 1 part cattail shoots, sliced Violet blossoms

Toss and add dressing to taste. Any combination of early garden greens can be substituted.

WATERCRESS DRESSING

(Maker 11/2 cups) 1/2 cup watercress 2 tablespoons sugar 1/4 cup cider vinegar 2 or 3 leeks (white part) 1 cup salad oil Salt and pepper to taste

In a blender or food processor whirl the watercress, sugar, vinegar and leeks to a liquified state. Add oil gradually and blend. Add salt and pepper to taste.

POKE WEED SOUFFLE

(4 to 6 servings) 1 cup (about 1/2 pound) poke weed or asparagus 1 cup bread crumbs 1 cup milk 1 can (8 ounces) chicken broth 4 eggs, separated 3/4 teaspon salt

Boil the poke weed twice for about 3 minutes each.

Change the water for each boiling. Puree. Combine the poke, bread crumbs, milk, chicken broth and egg yolks in th blender or food processor. Blend until creamy. Beat the egg white until stiff but not dry. Fold into the puree. Bake in a greased quart souffle dish in a 350 degree oven for 35 minutes or until golden. Serve hot. CAPTION: Picture, Botanist Jim Johnson, by James A. Parcell-The Washington Post