Squash (genus Cucurbita), genus of flowering plants in the gourd family (Cucurbitaceae), many of which are widely cultivated as vegetables and for livestock feed. Squash are fleshy vegetables protected by a hard rind. They belong to the plant family that includes melons and cucumbers. The skin and rind of summer squash are rich in the nutrient beta-carotene, but the fleshy portion of this vegetable is not. To gain the full nutritional benefits of this vegetable, the skins or rinds must be eaten.Summer squash is one of the most bountiful vegetables you can grow in your backyard. This crop grows very quickly in warm weather.