Rhizanthes is a genus of four species of parasitic flowering plants in the family Rafflesiaceae. They are without leaves, stems, roots, or photosynthetic tissue, and grow within the roots of a few species of Tetrastigma vines. The genus is limited to the tropical forests of Southeast Asia. The flowers of Rhizanthes are very large, they vary from 14 to 43 cm in diameter. At least one species of Rhizanthes, Rh. lowii, is endothermic.

The Rafflesiaceae are a family of rare parasitic plants comprising 36 species in 3 genera found in the tropical forests of east and southeast Asia, including Rafflesia arnoldii, which has the largest flowers of all plants. The plants are endoparasites of vines in the genus Tetrastigma (Vitaceae) and lack stems, leaves, roots, and any photosynthetic tissue. They rely entirely on their host plants for both water and nutrients, and only then emerge as flowers from the roots or lower stems of the host plants.