The common pumpkin is genus Cucurbita. Most are Cucurbita pepo or Cucurbita mixta. The giant pumpkin is Cucurbita maxima. Some are cultivars of Cucurbita moschata (butternut squash).
Pumpkin is botanically known as Cucrbita pepo. Its leaf is palmate and alternate.
The genus is Cucurbita in the family Cucurbitaceae (squash and gourds).