Artichokes are actually a type of thistle that is cultivated for food. We eat the flower buds. In particular, the edible portions are the fleshly lower parts of the leaves and the base (also called the heart). Artichokes contain good amounts of antioxidants, dietary fiber, folic acid, and vitamin C, and have been shown to aid in digestion and lower cholesterol.
Sprinkle with water and store in plastic bag in fridge for up to a week.
To prepare an artichoke for eating, first trim off any thorny tips on the leaves with scizzors, and pull off small leaves toward base and on stem. Rinse artichokes in cold water. Pour a couple inches of water in a pot, and add a clove of garlic, slice of lemon (or lemon juice), and a bay leaf for added flavor. Put artichokes in a steaming basket. Bring water to a boil, then reduce heat to a simmer and steam for 25-45 minutes or until outer leaves can be easily pulled off. (Smaller artichokes will take less time to cook.)
To eat, pull off petals, and dip the fleshy end in melted butter or sauce. Turn dip side down and pull past lower teeth to scrape of soft puply portion of the petal; discard remaining tough portion. Repeat for the rest of the petals. With a knife or spoon, scrape and discard the inedible fuzzy center portion (the choke) covering the heart. Cut heart into pieces and dip in butter/sauce to eat.
(Also see these great step-by-step directions with photos.)