Description from Flora of China
Nasturtium benghalense de Candolle, Syst. Nat. 2: 198. 1821, not Hance (1873); N. diffusum de Candolle; N. indicum (Linnaeus) de Candolle var. benghalense (de Candolle) J. D. Hooker & T. Anderson; Rorippa dubia (Persoon) H. Hara var. benghalensis (de Candolle) Mukerjee; R. indica (Linnaeus) Hiern subsp. benghalensis (de Candolle) Bennet; R. indica var. benghalensis (de Candolle) Debeaux.
Herbs annual, 15-65(-85) cm tall, glabrous or sparsely to densely hirsute, with spreading or retrorse trichomes. Stems simple at base, few to many branched above. Basal leaves soon withered. Lowermost cauline leaves auriculate; petioles to 3 cm; leaf blade oblong or oblong-obovate in outline, lyrate-pinnatipartite, (1.5-)2.5-12(-15) × (0.5-)1-4(-6) cm; terminal lobe broadly ovate or oblong, 1-5 × 0.7-3 cm; lateral lobes 1-4, oblong or ovate, to 2 × 1 cm, margin serrate or dentate. Upper leaves sessile, progressively reduced in size upward into bracts. Racemes bracteate throughout or rarely only along proximal third; bracts lanceolate-linear or oblong-linear, subentire or denticulate, minutely auriculate or cuneate at base. Fruiting pedicels ascending or divaricate, slender, straight, 3-6.5(-8) mm. Sepals elliptic or oblong, 1.5-2 × 0.5-0.8 mm. Petals pale yellow, spatulate or oblanceolate, 2-2.5 × 0.5-0.9 mm, apex rounded. Filaments 2-2.5 mm; anthers oblong, 0.4-0.5 mm. Ovules 100-170 per ovary. Fruit linear, straight or curved, 0.7-1.7(-2.1) cm × 1.2-1.6 mm; style 0.3-0.8 mm. Seeds reddish brown, subglobose or broadly ovoid, biseriate, 0.5-0.6 × 0.4-0.5 mm, minutely colliculate. Fl. and fr. Mar-Jul. 2n = 24, 48.
Although Rorippa benghalensis was first recorded from China by Hooker and Thomson (J. Proc. Linn. Soc., Bot. 5: 139. 1861, as Nasturtium benghalense), that record was overlooked by subsequent botanists. The occurrence of the species in China is here confirmed based on Wang 74232 (A), China-Russia Team 156 (KUN), and Yunnan Team 9474 (KUN).
Streamsides, wet grounds, marsh edges; near sea level to 1500 m. S Yunnan (Jinping Xian, Menglian Dai-Lahu-Va Zu Zizhixian) [Bangladesh, Bhutan, Cambodia, India, Laos, Malaysia, Myanmar, Nepal, Sikkim, Thailand, Vietnam].