26. Rheum uninerve Maximowicz, Bull. Acad. Imp. Sci. Saint-Pétersbourg. 26: 503. 1880.
单脉大黄 dan mai da huang
Herbs short, 15-30 cm tall. Roots slender. Stem absent. Basal leaves 2-4; petiole short, 3-5 cm, glabrous or rarely papilliferous; leaf blade ovate or narrowly ovate, 8-12 × 4-7.5 cm, papery, glabrous, main vein 1, lateral veins 8-10, base rounded or very broadly cuneate, margin sinuolate, apex obtuse or obtuse-acute. Panicle narrow, from apex of rhizome, 2-5 mm in diam., 1- or 2-branched, glabrous. Pedicel ca. 3 mm, slender, jointed at base. Flowers 2-4-fascicled; bracteole lanceolate, 1-2 mm. Tepals purple-red, elliptic, outer 3 smaller, 1-1.5 mm; disk circular, fleshy. Stamens 8 or 9, shorter than perianth; filaments very short, less than 1 mm. Ovary nearly rhomboid-ovoid; style long, reflexed; stigma inflated. Fruit broadly oblong-ellipsoid, 1.4-1.6 × 1.3-1.5 cm, base cordate, apex obtuse or retuse; wings purple-red, ca. 5 mm wide, membranous, with longitudinal veins near margin. Seeds dark brown, narrowly ovoid, ca. 3 mm wide. Fl. May-Jul, fr. Aug-Sep.
Slopes, roadsides; 1100-2300 m. Gansu, Nei Mongol, E Qinghai [Mongolia].