The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

low yellow-cress, Modoc yellow-cress, slender yellowcress, watercress, yellow cress

Columbia cress, Columbia yellow-cress, Columbia yellowcress cress, Columbian yellowcress

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

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
from FNA
CA; CO; ID; MO; MT; ND; NE; NM; NV; OR; SD; TX; UT; WA; WY; AB; BC; SK; Mexico (Baja California, Chihuahua)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR; WA
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 7, p. 505. FNA vol. 7, p. 499.
Parent taxa Brassicaceae > tribe Cardamineae > Rorippa Brassicaceae > tribe Cardamineae > Rorippa
Sibling taxa
R. alpina, R. amphibia, R. aquatica, R. austriaca, R. barbareifolia, R. calycina, R. columbiae, R. crystallina, R. curvipes, R. curvisiliqua, R. dubia, R. indica, R. microtitis, R. palustris, R. ramosa, R. sessiliflora, R. sinuata, R. sphaerocarpa, R. subumbellata, R. sylvestris, R. teres
R. alpina, R. amphibia, R. aquatica, R. austriaca, R. barbareifolia, R. calycina, R. crystallina, R. curvipes, R. curvisiliqua, R. dubia, R. indica, R. microtitis, R. palustris, R. ramosa, R. sessiliflora, R. sinuata, R. sphaerocarpa, R. subumbellata, R. sylvestris, R. tenerrima, R. teres
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)
Web links