1.1.1- The Order Cucurbitales The Cucurbitales are an order of flowering plants, included in the rosid group of dicotyledons. This order mostly belongs to tropical areas, with limited presence in subtropic and temperate regions. The order includes shrubs and trees, together with many herbs and climbers. The present classification is due to APG III (2009). The Order Cucurbitales consists of roughly 2600 species in eight families in which the Cucurbitaceae (gourd family) with 960 species. This large family include several economically important plants. Specifically, the Cucurbitaceae (gourd family) are responsible for some food species, such as squash, pumpkin (both from Cucurbita), melons including watermelon (Citrullus vulgaris), and cucumber (Cucumis). One of major characteristics of the Cucurbitales is the presence of unisexual flowers, mostly pentacyclic, with thick pointed petals (whenever present). The pollination is usually performed by insects, but wind pollination is also present (in Coriariaceae and Datiscaceae). 1.1.2-The Family Cucurbitaceae The Family Cucurbitaceae (also called gour family) consist of approximately 125 genera and 960 species, mainly in regions tropical and subtropical. Most of the plants in this family are annualvines but there are also woody lianas, thorny shrubs, and trees (Dendrosicyos). Many species have large, yellow or white flowers. The stems are hairy and pentangular. Tendrils are present at 90° to the leaf petioles at nodes. Leaves are exstipulate alternate simple palmately lobed or palmately compound. The flowers are unisexual, with male and female flowers on different plants (dioecious) or on the same plant (monoecious). The female flowers have inferior ovaries. The fruit is often a kind of modified berry called a pepo. The Cucurbitaceae sometimes called the gourdfamily, consisting of over a hundred genera, the most important families of which are: Cucurbita : squash, pumpkin, zucchini, some gourds Lagenaria: mostly non-edible gourds Citrullus : watermelon (Citrullus lanatus) and others Cucumis: cucumber (Cucumis sativus), various melons Luffa: common name also luffa The plants in this family are grown around the tropics and in temperate areas, where those with edible fruits were among the earliest cultivated plants both in the Old and New World. The Cucurbitaceae family ranks among the highest of plant families for number and percentage of species used as human food. 1.1.3- Genus Cucurbita Genus Cucurbita (Latin for gourd) is a genus in the gourd familyCucurbitaceae native to and originally cultivated in the Andes and Mesoamerica. The Cucurbita genus is an important source of human food and is used for other purposes such as beverages, medicine, oil, and detergent. Some Cucurbita species were brought to Europe after the discovery of America and are now used in many parts of the world. The plants, referred to as squash, pumpkin or gourd depending on species, variety and local parlance, are grown for their edible fruits and seeds. There is no universal agreement on how to handle the taxonomic treatment of the genus, with the number of species being listed varying from 13-30. There is uncertainty as to the ancestors of some species. There are five major domesticated species: 1- Cushaw Pumpkin (Cucurbita argyrosperma) 2- Asian Pumpkin (Cucurbita ficifolia) 3- Cucurbita maxima, 4- Cucurbita moschata, 5- Cucurbita pepo. 1.1.4- Pumpkin plants Pumpkin is the name of a plant that refers to certain cultivars of squash (fruits of Genus Cucurbita), most commonly those of Cucurbita pepo, that are 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. Specific cultivars of winter squash derived from other species, including C. argyrosperma, and C. moschata, are also sometimes called "pumpkin". In New Zealand and Australian English, the term "pumpkin" generally refers to the broader category called winter squash elsewhere. Pumpkins, like other squash, are native to North America. Pumpkins are widely grown for commercial use, and are used both in food and recreation. Pumpkin pie, for instance, is a traditional part of Thanksgiving meals in the United States, although commercially canned pumpkin puree and pumpkin pie fillings are usually made from different kinds of winter squash than the pumpkins frequently carved as jack o'lanterns for decoration around Halloween.