Rheum

From eagle-rock.org

Rheum is a genus of about 60 perennial plants in the family Polygonaceae. The genus includes the vegetable rhubarb (Rheum rhabarbarum or Rheum x hybridum.) The species have large somewhat triangular shaped leaves with long, fleshy petioles. The flowers are small, greenish-white to rose-red, and grouped in large compound leafy inflorescences. A number of varieties of rhubarb have been domesticated both as medicinal plants and for human consumption. While the leaves are toxic, the stalks are used in pies and other foods for their tart flavor.

See Rheum(genus) - Wikipedia