11. Rorippa dubia (Persoon) H. Hara, J. Jap. Bot. 30: 196. 1955.
Sisymbrium dubium Persoon, Syn. Pl. 2: 199. 1806, based on S. apetalum Desfontaines, Tabl. École Bot., 130. 1804, not Loureiro 1790; Nasturtium heterophyllum Blume; Rorippa heterophylla (Blume) R. O. Williams; R. indica (Linnaeus) Hiern var. apetala (de Candolle) Hochreutiner
Annuals; usually glabrous, rarely sparsely pubescent. Stems (simple or branched from base), erect or ascending, branched proximally and distally, (0.4-)1.5-3.3(-4.5) dm, (glabrous or sparsely pubescent proximally). Basal leaves not rosulate; blade margins pinnatifid. Cauline leaves petiolate (to 4 cm) or (distal) sessile; blade lyrate-pinnatipartite or undivided, obovate, oblong, or lanceolate, (2-)3-11(-15) cm × (5-)10-30(-50) mm, (lateral lobes smaller than terminal), base auriculate or not, margins entire, irregularly crenate, or serrate (entire or serrulate distally). Racemes elongated. Fruiting pedicels divaricate, straight, (2-)3-8(-10) mm. Flowers: sepals erect, oblong-linear, (2-)2.5-3 × 0.5-0.7 mm; petals (usually absent), yellow, linear or narrowly oblanceolate, 1-1.5 × 0.2-0.7 mm, (shorter than sepals); median filaments 1.5-2.8 mm; anthers oblong, 0.5-0.8 mm. Fruits siliques, straight, linear, (15-)25-40 × 0.7-0.9(-1) mm; ovules 70-90 per ovary; style 0.2-1(-1.5) mm, (stout, as thick as fruit). Seeds uniseriate, reddish brown, ovate-orbicular, 0.5-0.8 mm (0.4-0.6 mm diam.), foveolate. 2n = 32, 48.
Flowering often year-round. Waste areas, slopes, roadsides, wet grounds, grassy places, field margins; 0-500[-3700] m; introduced; La., Miss., Oreg.; se Asia; introduced also in Central America, South America.
Rorippa dubia was treated by R. L. Stuckey (1972) as R. heterophylla and by R. C. Rollins (1993) as R. indica var. apetala. Both authors overlooked H. Hara’s (1955b) comprehensive account of its typification and that of R. indica.