Rhododendron root is the root of what tree?

Rhododendron root is the root of Rhododendron tree.

Rhododendron tree, deciduous shrub, 2(-5) meters high; Branches numerous and slender, densely bright brown strigose. Leaves leathery, often branched, oval, oval or obovate or obovate to oblanceolate, 5-5cm long and 0 wide. 5-3 cm, the apex is short and tapering, the base is cuneate or broadly cuneate, the edge is slightly rolled back, the teeth are thin, the upper part is dark green, sparsely rough, the lower part is pale white, densely brown rough, and the midvein is concave and convex; Petiole 2-6 mm long, densely covered with bright brown flat strigose.