5. Rheum wittrockii C. E. Lundström, Acta Horti Berg. 5(3): 23. 1914.
天山大黄 tian shan da huang
Herbs large, 50-100 cm tall. Rhizomes dark brown, slender. Stem hollow, finely sulcate, glabrous or papilliferous near nodes. Basal leaves 2-4; petiole ca. as long as blade, slender, sparsely papilliferous or glabrous; leaf blades ovate to triangular-ovate, 15-26 × 10-20 cm, abaxially pubescent near veins, adaxially glabrous, basal veins 5-7, base cordate, margin sinuolate, apex obtuse or acute. Stem leaves 2-4, shortly petiolate, smaller than basal ones, longer than wide; ocrea 4-8 cm, abaxially pubescent, clasping. Panicle large, sparsely branched. Pedicel ca. 3 mm, jointed below middle. Flowers small, ca. 2 mm. Tepals white-green, outer 3 smaller and narrower; inner 3 slightly larger, obovate or broadly elliptic, ca. 1.5 mm. Stamens equal to perianth. Styles 3; stigmas large, muricate. Fruit orbicular or oblong, broader than long, ca. 1.2 × 1.5 cm, both ends cordate; wings broad, 4-5 mm, with longitudinal veins at middle. Seeds ovoid, ca. 6 mm wide. Fl. Jun-Jul, fr. Aug-Sep.
Grassy slopes, forests, gullies; 1200-2600 m. Xinjiang [Kazakhstan, Kyrgyzstan].