A pumpkin is commonly of Cucurbita pepo, that is round, with smooth, slightly ribbed skin, and deep yellow to orange coloration. The thick shell contains the seeds and pulp. Some exceptionally large cultivars of squash with similar appearance have also been derived from Cucurbita maxima. In New Zealand and Australian English, the term pumpkin generally refers to the broader category called winter squash elsewhere. Native to North America, pumpkins are widely grown for commercial use and are used both in food and recreation. Pumpkins are very versatile in their uses for cooking. Most parts of the pumpkin are edible, including the fleshy shell, the seeds, the leaves, and even the flowers. Pumpkin is sometimes prepared and frozen for later use.