Lepidium appelianum |
Lepidium barnebyanum |
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globe-pod hoary-cress, hairy whitetop, white-top |
Barneby's pepperweed |
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Habit | Perennials; (rhizomatous); often densely hirsute. | Perennials; (cespitose, caudex thick, woody, numerous-branched, with persistent petiolar remains); puberulent. |
Stems | simple or several from base, erect or ascending, branched distally, (1–)1.5–3.5(–5) dm. |
simple or few from base (caudex), erect to ascending, unbranched or branched distally, (0.3–)0.5–1.5(–1.7) dm. |
Basal leaves | (often withered by anthesis); not rosulate; petiole 0.5–1.5 cm; blade obovate to oblanceolate, (1–)2–6(–7) cm × 3–20 mm, margins dentate to sinuate. |
not rosulate; petiole 0.3–0.8 cm, (papery); blade linear, (0.5–)1–7(–8) cm × 10–36 mm, margins entire. |
Cauline leaves | sessile; blade oblong or lanceolate, 1–5(–8) cm × (3–)5–15(–30) mm, base sagittate, margins dentate or subentire, (surfaces pubescent). |
sessile; blade linear, base attenuate, not auriculate, margins entire, (similar to basal, smaller distally). |
Racemes | (usually corymbose, rarely paniculate), rarely elongated in fruit; rachis pubescent, trichomes often curved. |
slightly elongated in fruit; rachis puberulent, trichomes straight. |
Flowers | sepals oblong, 1.4–2 × 0.7–1 mm; petals white, broadly obovate, (2.2–)2.8–4 × 1–3 mm, claw 1–1.4 mm; stamens 6; filaments 2–2.5 mm, (glabrous); anthers 0.4–0.5 mm. |
sepals (sometimes somewhat persistent), oblong-obovate, 1.8–2.8 × 1.3–1.8 mm; petals white to pale yellow, suborbicular to broadly obovate, 3.2–4.6 × 2.5–3.2 mm, claw 0.5–1.5 mm; stamens 6; filaments 1.8–2.6 mm, (glabrous); anthers 0.5–0.8 mm. |
Fruiting pedicels | divaricate to ascending, straight or slightly curved, (terete), 3–9(–12) × 0.2–0.3 mm, pubescent. |
divaricate-ascending, straight, (terete), 3–8 × 0.3–0.4 mm, puberulent throughout. |
Fruits | (indehiscent), globose or, rarely, subglobose, (2–)3–4.4(–5) mm diam., (inflated), apically not winged, apical notch absent; valves thin, smooth, not veined, densely puberulent; style 0.5–1.5 mm. |
ovate, 4–5.5(–6.2) × 3–3.8 mm, apically winged, apical notch 0–0.2 mm deep; valves thin, smooth, not veined, glabrous; style 0.5–1.2 mm, exserted beyond apical notch. |
Seeds | (brown or dark brown), ovoid, 1.5–2 × 1–1.5 mm. |
ovate, 2.2–2.8 × 1.4–1.6 mm. |
2n | = 16. |
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Lepidium appelianum |
Lepidium barnebyanum |
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Phenology | Flowering May–Sep. | Flowering May–Jun. |
Habitat | Roadsides, sagebrush communities, alkaline meadows, waste grounds, ditch and stream sides, fields, pastures | Pinyon-juniper and sagebrush communities, white sandy shale |
Elevation | 400-2400 m (1300-7900 ft) | 1800-2000 m (5900-6600 ft) |
Distribution |
CA; CO; ID; MI; MO; MT; ND; NE; NM; NV; OR; PA; UT; WA; WI; WY; AB; BC; MB; SK; c Asia [Introduced in North America; introduced also in South America, other parts of Asia]
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UT |
Discussion | Lepidium appelianum has become a noxious weed in most of its range in North America. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Lepidium barnebyanum is known from the Green River and Uinta Shale Formations in Duchesne 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.) |
Source | FNA vol. 7, p. 576. | FNA vol. 7, p. 576. |
Parent taxa | Brassicaceae > tribe Lepidieae > Lepidium | Brassicaceae > tribe Lepidieae > Lepidium |
Sibling taxa | ||
Synonyms | Hymenophysa pubescens, Cardaria pubescens, Cardaria pubescens var. elongata | L. montanum subsp. demissum |
Name authority | Al-Shehbaz: Novon 12: 7. (2002) | Reveal: Great Basin Naturalist 27: 178. (1967) |
Web links |
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