Cardamine micranthera |
Cardamine occidentalis |
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streambank bittercress |
big western bitter-cress, western bitter-cress, western toothwort |
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Habit | Perennials; glabrous throughout. | Perennials; glabrous or hirsute. |
Rhizomes | (relatively short), 2–3 mm diam., (covered with extensive root system). |
(tuberiform, fragile), ovoid or globose at base of stem, 3–10 mm diam., (fleshy). |
Stems | erect to ascending, unbranched or branched distally, 0.9–4 dm. |
(simple from base), erect to ascending, (not flexuous), unbranched or branched distally, 1–5 dm, glabrous or pubescent proximally. |
Basal leaves | not rosulate, pinnately compound, (3 or) 5 (or 7)-foliolate, 2–10 cm, leaflets petiolulate or subsessile; petiole 0.5–6.5 cm; lateral leaflets petiolulate or subsessile, blade similar to terminal, ovate, smaller, margins entire; terminal leaflet (petiolule 0.03–0.18 cm), blade orbicular to broadly ovate or subcordate, 0.5–2 cm × 7–25 mm, base cordate to rounded, margins entire or repand, (surfaces glabrous). |
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Rhizomal leaves | usually 3-foliolate, rarely simple, 1–8 cm, leaflets petiolulate or subsessile; petiole 0.5–5 cm; lateral leaflets subsessile, often minute; terminal leaflet (petiolule 0.4–2 cm), blade orbicular to broadly ovate, 0.5–3 cm × 5–25 mm, base rounded, margins entire, repand, or dentate. |
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Cauline leaves | 5–10, petiolate; middle leaves often simple, petiole 0.3–1.5 cm, blade rhombic to suborbicular or ovate, 1–3.5 cm × 6–22 mm, base obtuse to cuneate, margins entire, repand, or dentate; distal ones with shorter petiole, blade smaller. |
3–7, (3 or) 5 or 7-foliolate (middle ones 5 or 7-foliolate, smaller distally, becoming 3-foliolate), petiolate; petiole 0.5–3 cm, base not auriculate; lateral leaflets similar to terminal, smaller; terminal leaflet blade obovate to oblanceolate, 0.5–2.6 cm × 3–13 mm, margins shallowly toothed, entire, or repand. |
Racemes | ebracteate. |
ebracteate. |
Flowers | sepals (ascending), oblong, 1.5–2.2 × 0.7–1 mm, lateral pair not saccate basally; petals (somewhat spreading), white, oblanceolate, 3.5–5 × 1.2–1.8 mm, (not clawed, apex rounded); filaments: median pairs 2.5–3 mm, lateral pair 2–2.5 mm; anthers ovate, ca. 0.2 mm. |
sepals oblong, 1.7–2 × 1–1.2 mm, lateral pair not saccate basally; petals white, oblanceolate, 4–6 × 1.5–2 mm, (not clawed); filaments: median pairs 2–2.5 mm, lateral pair 1–1.5 mm; anthers ovate, 0.3–0.5 mm. |
Fruiting pedicels | divaricate, 9–17 mm. |
divaricate-ascending, 7–18 mm. |
Fruits | linear, 0.8–1.6 cm × 0.8–1 mm; ovules 16–22 per ovary; style 1.2–1.8 mm. |
linear, (torulose), 1.5–3.3 cm × 1.7–2.2 mm; (valves glabrous or sparsely pubescent); ovules 18–40 per ovary; style 0.5–1.5 mm. |
Seeds | brown, oblong to ovoid, 0.9–1.2 × 0.6–0.8 mm. |
brown, ovoid, 1–1.6 × 1–1.2 mm. |
2n | = 64. |
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Cardamine micranthera |
Cardamine occidentalis |
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Phenology | Flowering Apr–May. | Flowering Apr–Jul. |
Habitat | Wet grounds along streams, seepage, gravelly sandbars, moist crevices | Muddy grounds, lake margins, shallow streams, meadows |
Elevation | 150-1500 m (500-4900 ft) | |
Distribution |
NC |
AK; CA; OR; WA; BC
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Discussion | Of conservation concern. Cardamine micranthera is known only from Stokes County. It is in the Center for Plant Conservation’s National Collection of Endangered Plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 7, p. 477. | FNA vol. 7, p. 479. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | C. pratensis var. occidentalis, C. neglecta | |
Name authority | Rollins: Castanea 5: 87. (1940) | (S. Watson) Howell: Fl. N.W. Amer., 50. (1897) |
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