An ancient Greek pundit once advised, "Eat more cress and learn wit." This prophet may have been without honor in his own land, but the Romans took him seriously enough to consume quantities of the leafy green with vinegar as a remedy for unbalanced minds.

Today we eat this tasty member of the mustard family as a garnish or ingredient for innumerable dishes.

Watercress is perishable if not stored properly. If you don't plan to use it on the day of purchase, rinse the bunch, place stems in a jar of cold water, cover the leaves with a loose plastic bag, and secure the bag against the jar. Store in the refrigerator as long as a week.

The very high vitamin A content of watercress makes it a valuable addition to the diet. This small, round leaved plant is low in calories, but a good source of vitamin C. One bunch of watercress contains only 3.3 grams of carbohydrate.

WATERCRESS MAYONNAISE:

1 c. watercress leaves
4 shallots, peeled and halved
1 egg yolk
2 tbsp. tarragon vinegar
2 tbsp. lemon juice
1 tsp. Dijon mustard
1/4 tsp. sugar
1/4 tsp. salt
1 c. mayonnaise
1 c. sour cream

In the container of a blender put watercress, shallots, egg yolk, tarragon vinegar, lemon juice, Dijon mustard, sugar and salt. Blend the mixture for about 1 minute, pushing the greens into the blades if necessary. Add mayonnaise and sour cream and blend the sauce until it is smooth. Serve very cold.