Rheum L.
Stout perennial herbs forming large clumps; rhizomes ± woody. Lvs mainly radical, large, ovate to reniform, ± cordate, palmately veined; ochreae prominent and loose. Fls in large diffuse panicles, ⚥, green, whitish or red. Perianth segments 6, free, equal, not accrescent, not keeled. Stamens (6)-9. Styles 3, very short; stigmas capitate. Fr. a trigonous nut, strongly 3-winged, lacking spines.
25-40 spp., Asia. Naturalised sp. 1.