Dandelion

Almost everyone recognizes a dandelion (Taraxacum spp.), but not everyone realizes that nearly every part of the plant is edible. The leaves, which are most palatable in spring before the plant flowers, are high in iron, beta-carotene, and potassium. Dandelions are also mildly diuretic.

Read more: http://www.herbcompanion.com/Cooking/Weed-Eater.aspx#ixzz1reCJOR7X
For a delicacy that tastes like mushrooms, collect a colander full of dandelion blossoms, wash them, dust them with flour seasoned with salt and pepper, then pan-fry them in a bit of butter. The blossoms may also be used to make wine.
I like to sauté well-scrubbed dandelion roots in a little toasted sesame oil and tamari sauce. Herbalists have long prescribed dandelion root tea to relieve acne and eczema as well as to enhance liver function.

From this month's Herb Companion