Rorippa tenerrima |
Rorippa columbiae |
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low yellow-cress, Modoc yellow-cress, slender yellowcress, watercress, yellow cress |
Columbia cress, Columbia yellow-cress, Columbia yellowcress cress, Columbian yellowcress |
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Habit | Annuals; (terrestrial or of wet habitat, not submerged); glabrous throughout. | Perennials; (terrestrial or of wet habitat, not submerged, with creeping roots and adventitious stems); pilose or hirsute. |
Stems | (several-branched from base), prostrate to decumbent, branched distally, 0.7–3.5(–4) dm. |
suberect or decumbent to prostrate, branched distally, 1–3.2(–4.1) dm, (pilose to hirsute). |
Basal leaves | not rosulate; blade margins pinnatifid. |
absent. |
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. |
shortly petiolate or sessile; blade oblanceolate to oblong, (lateral lobes oblong to ovate, often reaching midrib), 2.4–5.2 cm × 5–12 mm, base auriculate or not, margins sinuate to pinnatifid or (lateral lobes) entire or dentate, (surfaces pilose). |
Racemes | elongated. |
elongated. |
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. |
sepals (persistent), ascending, oblong, 2–3.5 × 0.8–1.5 mm, (pilose); petals yellow, oblanceolate to spatulate, 2.7–4.2 × 0.7–1.7 mm; median filaments 2–3.5 mm; anthers ovate, ca. 0.8 mm. |
Fruiting pedicels | ascending to divaricate, (1–)1.5–3.2(–4.2) mm, straight. |
ascending, (subappressed to rachis), straight, (3–)4–10(–12) mm, (densely pilose). |
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. |
silicles, straight, subglobose to oblong ellipsoid, (1.5–)2.5–5.5(–7) × (1–)1.7–2.8(–3.5) mm; valves densely pilose; ovules 24–40 per ovary; style 0.7–3.2 mm, (pilose). |
Seeds | biseriate, reddish brown, cordiform, 0.5–0.7 mm, colliculate. |
biseriate, yellowish brown, ovoid-globose, 0.7–0.9 mm, prominently colliculate. |
Rorippa tenerrima |
Rorippa columbiae |
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Phenology | Flowering Jun–Oct. | Flowering Jun–Aug. |
Habitat | Shores of lakes and ponds, mud flats, marshes, sand bars, moist grounds, streamsides | Stream banks, ditches, margins of lakes and ponds, meadows, roadsides, gravel bars, wet fields |
Elevation | 1300-3000 m (4300-9800 ft) | 100-1600 m (300-5200 ft) |
Distribution |
CA; CO; ID; MO; MT; ND; NE; NM; NV; OR; SD; TX; UT; WA; WY; AB; BC; SK; Mexico (Baja California, Chihuahua)
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CA; OR; WA
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Source | FNA vol. 7, p. 505. | FNA vol. 7, p. 499. |
Parent taxa | Brassicaceae > tribe Cardamineae > Rorippa | Brassicaceae > tribe Cardamineae > Rorippa |
Sibling taxa | ||
Synonyms | Radicula tenerrima | Nasturtium sinuatum var. columbiae, Nasturtium columbiae, Nasturtium sinuatum var. pubescens, Radicula columbiae, R. calycina var. columbiae, R. sinuata var. pubescens |
Name authority | Greene: Erythea 3: 46. (1895) | (S. Watson) Howell: Fl. N.W. Amer., 40. (1897) |
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