Cardamine flexuosa Withering, Arr. Brit. Pl., ed. 3, 3: 578. 1796; C. hirsuta subsp. flexuosa (Withering) J. D. Hooker, ……..; C. hirsuta Linnaeus subsp. flexuosa (Withering) Forbes & Hemsl., J. Linn. Soc., Bot. 23: 43. 1886; C. hirsuta Linnaeus var. flexuosa (Withering) J. D. Hooker & T. Anderson in J. D. Hooker, Fl. Brit. India 1: 138. 1872; C. scutata Thunberg subsp. flexuosa (Withering) H. Hara, J. Fac. Sci. Univ. Tokyo III, 6: 59. 1952. TYPE: England, Rockery at Edgbaston (lectotype designated by Post et al. (2009: 227), Curtis t. 277. 1777).

Cardamine arisanensis Hayata, Icon. Pl. Formos. 3: 20. 1912; Barbarea arisanensis (Hayata) S. S. Ying, Alp. Pl. Taiwan Color. 2: 170. 1978. TYPE:

Cardamine debilis D. Don, Prodr. Fl. Nepal. 201. 1825, not Banks ex de Candolle, Syst. Nat. 2: 265. 1821; Cardamine flexuosa Withering subsp. debilis O. E. Schulz, Bot. Jahrb. Syst. 32: 478. 1903; Cardamine flexuosa Withering var. debilis (O. E. Schulz) T. Y. Cheo & R. C. Fang, Bull. Bot. Lab. North-East. Forest. Inst., Habrin (1980)6: 23. 1980. TYPE:

Cardamine sylvatica Link var. kamtschatica Regel, Bull. Soc. Imp. Naturalistes Moscou 34: 172. 1861; C. flexuosa Withering var. kamtschatica (Regel) Matsumura, Bot. Mag. (Tokyo) 13: 73. 1899. TYPE:

Cardamine flexuosa Withering var. ovatifolia T. Y. Cheo & R. C. Fang, Bull. Bot. Lab. North-East. Forest. Inst., Habrin (1980)6: 24. 1980. TYPE: China. Zhejiang: Hangchow Longjing, 21 March 1957, S. Y. Chang 186 (holotype, NAS).

Cardamine hirsuta Linnaeus var. flaccida Franchet, Bull. Soc. Bot. France 33: 398. 1886. TYPE: China. Yunnan, Mosoyn, near Lankong, 14 March 1885, Delavay 1839 (holotype, P!; isotype, US!).

Cardamine hirsuta Linnaeus var. omeiensis T. Y. Cheo & R. C. Fang, Bull. Bot. Lab. North-East. Forest. Inst., Habrin 6: 23. 1980. TYPE: China. Sichuan: Mount Omei, Jinding, 1 July 1938, 3035 m, H. C. Chou 7690 (holotype, WH (as HWH); isotypes, A!, NAS!).

Cardamine occulata Horneman, Hort. Hafn. Suppl. 71. 1919; C. flexuosa Withering subsp. debilis var. occulata (Horneman) O. E. Schulz, Bot. Jahrb. Syst. 32: 479. 1903. TYPE:

Cardamine sylvatica Link in Hoffmann, Phyt. Blätt. 1: 50. 1803. TYPE:

Cardamine zollingeri Turczaninow, Bull. Soc. Imp. Naturalistes Moscou 28: 294. 1854.

Nasturtium obliquum Zollinger & Mor., Nat. en Geneesk. Arch. Neerl. Indie 2: 580. 1845. TYPE:

            Herbs, annual or biennial, sparsely to densely hirsute basally or throughout, or glabrous. Stem (6–)10–50 cm, erect, ascending, or decumbent, 1 to several from base, simple or branched, flexuous or straight. Basal leaves not rosulate, often withered by anthesis, petiolate; leaf blade (2–)4–10(–14) cm, lyrate; terminal lobe reniform, broadly ovate, or suborbicular, repand or 3–5-lobed; lateral lobes, (1 or)2–6(or 7) on each side of midvein, petiolulate or subsessile, oblong, ovate, or elliptic, smaller than terminal lobe, entire, repand, crenate, or 3(–5)-lobed; cauline leaves 3–15, including petiole (2–)3.5–5.5(–7) cm; petiole base not auriculate; terminal lobe 3–5-lobed; lateral lobes 2–7 on each side of midvein, suborbicular, ovate, oblong, oblanceolate, or linear, similar to or slightly smaller than terminal lobe, sessile or shortly petiolulate, entire, repand, dentate, or 3(–5)-lobed. Raceme ebracteate, several flowered; fruiting pedicels divaricate or ascending, (5–)6–14(–17) mm, slender. Sepals oblong, 1.5–2.5 ´ 0.7–1 mm; petals white, spatulate, 2.5–4(–5) ´ 1–1.7 mm; stamens 6, rarely 4 and lateral pair absent; filaments 2–3 mm; anthers ovate, 0.3–0.5 mm; ovules 18–40 per ovary. Fruit linear, (0.8–)1.2–2.8 cm ´ 1–1.5 mm; valves glabrous, torulose; style 0.3–1(–1.5) mm. Seeds brown, oblong or subquadrate, 0.9–1.5 ´ 0.6–1 mm, narrowly margined or not. 2n = 32.

Flowering: Feb–Jun.

Habitat: Fields, roadsides, grasslands, disturbed sites, streamsides, clearings, running water, wet forests, dry sites, greenhouses.

Elevation: 0–3600 m.

Distribution: native in Europe (all countries except Iceland); naturalized in Africa (Algeria, Morocco), Asia [Bangladesh, Bhutan, China (Guangdong, Guizhou, Sichuan, Yunnan), India (Sikkim), Indonesia, Japan, Kashmir, Korea, Laos, Malaysia, Myanmar, Nepal, Pakistan, Philippines, Taiwan, Thailand, Vietnam], naturalized in Australia, North America [Canada (British Columbia, Newfoundland, Ontario), United States (Alabama, California, Florida, Georgia, Illinois, Indiana, Louisiana, Maryland, Michigan, New York, North Carolina, Ohio, Oregon, Rhode Island, Texas, Virginia, Washington)], Central America (Mexico), and South America [Argentina (Corrientes, Jujuy, Salta), Bolivia (La Paz, Santa Cruz), Brazil (Linhares-Espirito Santo), Colombia (Antioquia), Paraguay, Peru (Cajamarca, Pasco), Venezuela (Bolivar, Distrito Federal, Miranda, Trujillo)].