Rorippa tenerrima

Annuals; (terrestrial or of wet habitat, not submerged); glabrous throughout. Stems (several-branched from base), prostrate to decumbent, branched distally, 0.7–3.5(–4) dm. Basal leaves not rosulate; blade margins pinnatifid. Cauline leaves shortly petiolate, or (distal) sessile; blade oblong to oblanceolate or lanceolate, (lateral lobes linear, oblong to ovate, or obovate), 2–9(–11) cm × 7–20(–30) mm, (lateral lobes smaller than terminal), base not auriculate, margins pinnatifid, or (lateral lobes) entire, dentate, or sinuate. Racemes elongated. Fruiting pedicels ascending to divaricate, (1–)1.5–3.2(–4.2) mm, straight. Flowers: sepals ascending, oblong, 0.7–1.3 × 0.4–0.7 mm; petals yellow, oblong to oblanceolate or spatulate, 0.5–0.8 × 0.1–0.3 mm; median filaments 0.8–1.2 mm; anthers ovate, 0.1–0.2 mm. Fruits siliques or silicles, curved-ascending, lanceolate to narrowly ovoid or oblong-lanceolate, 3–7(–9) × (0.8–)1–1.7(–2) mm (often slightly constricted at middle); valves papillate; ovules 20–80 per ovary; style (0.2–)0.5–1 mm. Seeds biseriate, reddish brown, cordiform, 0.5–0.7 mm, colliculate.

Phenology: Flowering Jun–Oct.
Habitat: Shores of lakes and ponds, mud flats, marshes, sand bars, moist grounds, streamsides
Elevation: 1300-3000 m

Distribution

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• Legacy Map

Alta., B.C., Sask., Calif., Colo., Idaho, Mo., Mont., Nebr., Nev., N.Mex., N.Dak., Oreg., S.Dak., Tex., Utah, Wash., Wyo., Mexico (Baja California, Chihuahua).

Discussion

Selected References

None.

Lower Taxa

None.