Lepidium alyssoides |
Lepidium appelianum |
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mesa pepperwort |
globe-pod hoary-cress, hairy whitetop, white-top |
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Habit | Perennials or subshrubs; (woody base often aboveground); glabrous or minutely puberulent. | Perennials; (rhizomatous); often densely hirsute. |
Stems | few to several from base, erect to ascending, branched throughout, (0.7–)1–4.8(–6.1) dm. |
simple or several from base, erect or ascending, branched distally, (1–)1.5–3.5(–5) dm. |
Basal leaves | often not rosulate; petiole 1–6 cm; blade pinnately lobed, (1–)1.5–8(–11) cm × (5–)10–35 mm, margins (of lobes) entire or denticulate. |
(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. |
Cauline leaves | sessile; blade linear, (0.8–)1.3–7(–9.5) cm × (0.7–)1–2(–3) mm, base attenuate, not auriculate, margins entire. |
sessile; blade oblong or lanceolate, 1–5(–8) cm × (3–)5–15(–30) mm, base sagittate, margins dentate or subentire, (surfaces pubescent). |
Racemes | elongated in fruit; rachis puberulent or glabrous. |
(usually corymbose, rarely paniculate), rarely elongated in fruit; rachis pubescent, trichomes often curved. |
Flowers | sepals ovate to oblong, 1–2 × 0.8–1 mm; petals white, suborbicular, 2–3 × 1–2 mm, claw 0.5–1.5 mm; stamens 6; filaments 1.5–2 mm, (glabrous); anthers 0.2–0.4 mm. |
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. |
Fruiting pedicels | divaricate to horizontal, straight or recurved to somewhat sigmoid, (terete), 3.5–8(–11) × 0.2 mm, glabrous or puberulent adaxially. |
divaricate to ascending, straight or slightly curved, (terete), 3–9(–12) × 0.2–0.3 mm, pubescent. |
Fruits | broadly ovate, 2–3.7(–4.3) × (1.5–)1.8–2.9(–3.4) mm, apically winged, apical notch 0.1–0.3(–0.4) mm deep; valves thin, smooth, not veined, glabrous; style 0.2–0.6 mm, exserted beyond apical notch. |
(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. |
Seeds | ovate, 1.5–1.8(–2) × 0.9–1.2(–1.5) mm. |
(brown or dark brown), ovoid, 1.5–2 × 1–1.5 mm. |
2n | = 32. |
= 16. |
Lepidium alyssoides |
Lepidium appelianum |
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Phenology | Flowering May–Jul. | Flowering May–Sep. |
Habitat | Pinyon-juniper or sagebrush communities, prairies, grasslands, sandstone outcrops, gypsum flats, sand dunes, dry flats and river bottoms, gravelly roadsides | Roadsides, sagebrush communities, alkaline meadows, waste grounds, ditch and stream sides, fields, pastures |
Elevation | 1200-2800 m (3900-9200 ft) | 400-2400 m (1300-7900 ft) |
Distribution |
AZ; CO; NM; NV; TX; UT; WY; Mexico (Chihuahua, Coahuila, Nuevo León, San Luis Potosí)
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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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Discussion | Of the five varieties of Lepidium alyssoides recognized by R. C. Rollins (1993), one (var. mexicanum Rollins) is a short-tufted form of the species restricted to Mexico that does not seem to merit recognition, another (var. junceum) is a glabrescent form of the type variety, a third (var. eastwoodiae) is treated below as a distinct species, and the fourth (var. angustifolium) is included here within L. alyssoides. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 7, p. 575. | FNA vol. 7, p. 576. |
Parent taxa | Brassicaceae > tribe Lepidieae > Lepidium | Brassicaceae > tribe Lepidieae > Lepidium |
Sibling taxa | ||
Synonyms | L. alyssoides var. angustifolium, L. alyssoides var. junceum, L. alyssoides var. minus, L. alyssoides var. polycarpum, L. alyssoides var. streptocarpum, L. montanum subsp. alyssoides, L. montanum var. alyssoides, L. montanum subsp. angustifolium, L. montanum var. angustifolium, L. tortum | Hymenophysa pubescens, Cardaria pubescens, Cardaria pubescens var. elongata |
Name authority | A. Gray: Mem. Amer. Acad. Arts, n. s. 4: 10. (1849) | Al-Shehbaz: Novon 12: 7. (2002) |
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