Description from Flora of China
Rheum micranthum Samuelsson; Rumex cacaliifolius H. Léveillé.
Herbs short, 25-55 cm tall. Roots black-brown, slender, ca. 1 cm in diam., few branched. Stem slender, hollow, 3.5-5 mm in diam., internode very long, not branched, slightly muricate, sparsely hispidulous. Basal leaves 1-3; petiole ca. as long as to 2 × as long as blade, slender, yellow hispidulous; leaf blade light green abaxially, green adaxially, ovate-cordate, triangular-ovate, or triangular-cordate, 6-11 × 4-8.5 cm, papery, abaxially sparsely hispidulous, with densely yellow hairs especially near margin, basal veins 5, middle one stout, base cordate, margin entire, apex slightly acuminate. Stem leaves 1 or 2, shortly petiolate, small; ocrea subovate, 1.5-2 cm, abaxially with white hairs, membranous when dry, not clasping. Panicle few branched, pubescent. Pedicel 2-3 mm, jointed at or below middle. Flowers small, 2-5-fascicled. Tepals 6, not spreading, white-green, rarely light purple, small, outer 3 smaller, nearly elliptic, inner 3 broadly elliptic, ca. 1.5 mm. Stamens 9 or fewer, slightly longer than perianth; anthers purple-red. Ovary rhomboid-ellipsoid or obovoid-ellipsoid; stigma inflated. Fruit broadly ovoid or subovoid, 6.5-8 mm, base cordate, apex retuse; wings red, narrow, ca. 1.5 mm wide, with longitudinal veins at middle. Seeds yellow-brown, with lanceolate black stripes at middle, narrowly ovoid, ca. 3 mm wide at base. Fl. Jun-Jul, fr. Jul-Aug.
* Slopes, forests; 2800-3900 m. Gansu, Sichuan, Yunnan.