The globe artichoke (Cynara cardunculus var. scolymus) is a perennial thistle of the Cynara genus originating in Southern Europe around the Mediterranean. It grows to 1.4–2 metres (4.6–6.6 ft) tall, with arching, deeply lobed, silvery, glaucous-green leaves 50–82 centimetres (20–32 in) long. The flowers develop in a large head from an edible bud about 8–15 centimetres (3.1–5.9 in) diameter with numerous triangular scales; the individual florets are purple. The edible portion of the buds consists primarily of the fleshy lower portions of the involucral bracts and the base, known as the “heart”; the mass of immature florets in the center of the bud is called the “choke” or beard. These are inedible in older larger flowers.
In the US, large globe artichokes are most frequently prepared for cooking by removing all but 5–10 millimetres (0.2–0.4 in) or so of the stem, and (optionally) cutting away about a quarter of each scale with scissors. This removes the thorns on some varieties that can interfere with handling the leaves when eating. Then, the artichoke is boiled or steamed until tender. The core of the stem, which tastes like the artichoke heart, is edible once the stem’s fibrous exterior has been removed
If boiling, salt can be added to the water, if desired. It may be preferable not to cover the pot while the artichokes are boiled, so the acids will boil out into the air. Covered artichokes, particularly those that have been cut, can turn brown due to the enzymatic browning and chlorophyll oxidation. If not cooked immediately, placing them in water lightly acidulated with vinegar or lemon juice prevents the discoloration.
Leaves are often removed one at a time and the fleshy base part is eaten, sometimes dipped in hollandaise, vinegar, butter, mayonnaise, aioli, lemon juice or other sauces, with the fibrous upper part of each leaf being discarded; the heart is then eaten when the inedible choke has been discarded after being carefully peeled away from the base. The thin leaves covering the choke are mostly edible.