7. Rheum forrestii Diels, Notes Roy. Bot. Gard. Edinburgh. 5: 262. 1912.
牛尾七 niu wei qi
Herbs 60-80 cm tall. Roots stout, 3-4 cm in diam. Stem erect, hollow, 0.8-1.4 cm in diam. at base, glabrous at lower part, yellow-white pubescent at upper part, especially at nodes. Basal leaves 3-5; petiole light green, subterete, ca. 1/2 as long as to subequal leaf blade, shortly hispid; leaf blade broadly ovate or ovate, 12-20 × 10-18 cm, abaxially densely hispid, adaxially pubescent or glabrous, basal veins 5-9, conspicuously raised abaxially, base cordate, margin entire, apex obtuse. Stem leaves 1 or 2, shortly petiolate, ovate or narrowly ovate, small; ocrea short, membranous when dry. Panicle branched from middle. Pedicel 2-3 mm, slender, jointed below middle. Flowers densely fascicled. Tepals yellow-green, broadly lanceolate, outer 3 smaller, ca. 1.8 × 1 mm, inner 3 larger, with a dark green longitudinal vein at middle. Stamens 8 or 9, shorter than perianth; filaments ca. 1 mm; anthers light purple-red, elliptic, ca. 1 mm. Ovary obovoid; stigma slightly inflated. Fruit very broadly ellipsoid or orbicular, 9-10 × 8-9.5 mm, base cordate, apex rounded; wings brown, narrow, ca. 1.5 mm wide, with longitudinal veins at middle. Seeds yellow-brown, ovoid-ellipsoid, 6-7 mm wide. Fl. Jun-Jul, fr. Aug-Sep.
* Slopes; ca. 3000 m. ?Sichuan, Xizang, Yunnan.