Cucurbita pepo, which encompasses summer squashes including zucchini, yellow crookneck, pattypan, and spaghetti, as well as some types of winter squash and pumpkin (Delicata squash, autumn pumpkin), is a frost-intolerant annual plant in the gourd family (Cucurbitaceae). Native to Mexico and North America, it is now widely cultivated in warm areas worldwide as a food and animal fodder.

C. pepo is one of the oldest known cultivated species, with Mexican archaeological evidence from 7,000 B.C. It is present in numerous sites in the southwestern and eastern U.S., dating from 800 B.C. to 1256 A.D. Thus, it was widely cultivated by indigenous peoples throughout Mexico, Central, and North America before the arrival of Europeans. It is now considered to have been domesticated in two separate episodes: in eastern North America, from C. texana; and in Mexico, from C. fraterna—with the two types interfertile, and giving rise to diverse varieties, sometimes divided into several subspecies.

Related species include C. maxima, C. mixta, and C. moschata, which include various cultivars known as winter squash and pumpkins. Some C. pepo cultivars are also called winter squash and pumpkins, so it can be difficult to ascertain which cultivars are derived from which species. In general, C. pepo fruits have a thin, edible rind, whereas other species have thick, leathery or hard, inedible rinds.

C. pepo is a non-trailing bush (in contrast to the vining habit of most cucurbits), upright and spreading, 45–75 cm (18–30 in) high. Fruits come in diverse forms, from oblong or elongate to flattened; some varieties have a crook neck. The fruit surface may be smooth, scalloped, ridged, or warty. Colors vary from white to cream to yellow to green; some are variegated or striped. Fruits develop rapidly after flowering, and must be harvested within just a few days, or the seeds and rinds will harden and flesh will become fibrous.

C. pepo fruits are eaten fresh in salads, boiled, baked, fried, or mashed and eaten as a vegetable, cooked in soups, or baked in pies and breads. Blossoms are edible, and may be breaded or battered and fried as fritters; a famous Italian dish, fiore di zucca, uses zucchini flowers. The fruits are low in calories but high in fiber. Seeds are high in protein, oil, and minerals (they contain 30% protein and 40–50% oil), and are eaten raw, toasted, or pressed to make oil.

In South and Central America, C. pepo has numerous traditional medicinal uses: seeds are toasted and eaten to kill intestinal parasites; fruits are used as a diuretic and anti-diabetic; and a preparation of the flowers has been used to treat jaundice, measles, and smallpox. Pumpkin seeds are sometimes used as a natural worming agent for sheep and goats by organic farmers, but their efficacy has not been clearly demonstrated.

World production of pumpkins, squashes, and gourds (across all species of Cucurbitaceae) was 22.1 million tons harvested from 1.7 million hectares in 2009, valued at $5.2 billion U.S. dollars. Leading producers were China, Russia, India, the U.S., and Egypt.

(Decker-Walters 1990, ECPGR 2008, Encyclopedia Britannica 1993, FAOSTAT 2011, NRC 1989, Schoenian 2011, Schultes 1990, Waynesword.com 2011, Whittaker and Davis 1962)