Cardamine micranthera |
Cardamine oligosperma |
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streambank bittercress |
alpine bitter-cress, few-seed bitter-cress, Idaho bittercress, little western bitter-cress, Siberian bitter-cress |
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Habit | Perennials; glabrous throughout. | Annuals or biennials; usually sparsely hirsute (at least proximally), rarely glabrous. |
Rhizomes | (relatively short), 2–3 mm diam., (covered with extensive root system). |
absent. |
Stems | erect to ascending, unbranched or branched distally, 0.9–4 dm. |
(simple or few from base), erect to ascending, (not flexuous), unbranched or branched distally, (0.5–)0.8–3.2(–4.1) dm, usually pubescent throughout or proximally, rarely glabrous. |
Basal leaves | (persistent to anthesis), rosulate, pinnately compound, 5–9(–13)-foliolate, 2–8.5(–11) cm, leaflets petiolulate or subsessile; petiole 1–6 cm; lateral leaflets petiolulate or subsessile, blade obovate to oblanceolate, smaller than terminal, margins entire or crenate; terminal leaflet (petiolule 0.1–0.7 cm), blade usually orbicular to ovate, rarely oblong, 0.4–1.5(–2.3) cm × 3–10(–13) mm, base cordate to rounded, margins entire, or crenate-dentate to obscurely 3 or 5-lobed, (surfaces often hirsute, sometimes 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. |
3–8, pinnately compound, similar to basal, smaller and fewer distally, petiolate, leaflets petiolulate or subsessile; petiole 0.5–2 cm, base not auriculate. |
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, 1.3–1.8(–2) × 0.5–1 mm, lateral pair not saccate basally; petals white, narrowly spatulate to oblanceolate, 2.5–3.5 × 0.9–1.5 mm (not clawed); filaments: median pairs 1.7–2.5 mm, lateral pair 1.2–2 mm; anthers ovate, 0.3–0.5 mm. |
Fruiting pedicels | divaricate, 9–17 mm. |
divaricate-ascending, (2–)3–9(–12) 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), (1.3–)1.6–2.8 cm × 1–1.7 mm; (valves glabrous or sparsely pubescent); ovules 16–36(–42) per ovary; style 0.4–1(–1.5) mm. |
Seeds | brown, oblong to ovoid, 0.9–1.2 × 0.6–0.8 mm. |
brown, oblong, 1–1.6 × 0.8–1.2 mm. |
2n | = 16. |
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Cardamine micranthera |
Cardamine oligosperma |
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Phenology | Flowering Apr–May. | Flowering Mar–Jul. |
Habitat | Wet grounds along streams, seepage, gravelly sandbars, moist crevices | Stream banks, shady banks, creek bottoms, lakeshores, meadows, moist areas, wooded slopes |
Elevation | 50-3300 m (200-10800 ft) | |
Distribution |
NC |
CA; CO; ID; MT; NV; OR; UT; WA; WY; BC; Mexico (Baja California)
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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. acuminata, C. hirsuta var. acuminata, C. hirsuta var. bracteata, C. hirsuta subsp. oligosperma, C. hirsuta var. parviflora, C. oligosperma var. bracteata, C. oligosperma var. lucens, C. oligosperma var. unijuga, C. unijuga | |
Name authority | Rollins: Castanea 5: 87. (1940) | Nuttall: in J. Torrey and A. Gray, Fl. N. Amer. 1: 85. (1838) |
Web links |
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