Lepidium didymum |
Lepidium alyssoides |
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lesser pepper-grass, lesser swine-cress, lesser wart-cress |
mesa pepperwort |
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Habit | Annuals; (fetid); glabrous or pilose. | Perennials or subshrubs; (woody base often aboveground); glabrous or minutely puberulent. |
Stems | few to several from base, erect to ascending or decumbent, branched distally, 1–4.5(–7) dm. |
few to several from base, erect to ascending, branched throughout, (0.7–)1–4.8(–6.1) dm. |
Basal leaves | (soon withered); not rosulate; petiole 0.5–4(–6) cm; blade 1- or 2-pinnatisect, 1–6(–8) cm, margins (of lobes) entire or dentate (sometimes deeply lobed). |
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. |
Cauline leaves | shortly petiolate to subsessile; blade similar to basal, smaller and less divided distally, lobes lanceolate to oblong or elliptic, 1.5–3.5(–4.5) cm ×5–12 mm, base not auriculate, margins (of lobes) entire, serrate, or incised. |
sessile; blade linear, (0.8–)1.3–7(–9.5) cm × (0.7–)1–2(–3) mm, base attenuate, not auriculate, margins entire. |
Racemes | elongated in fruit; rachis glabrous or pubescent, trichomes straight, cylindrical. |
elongated in fruit; rachis puberulent or glabrous. |
Flowers | sepals (tardily deciduous), ovate, 0.5–0.7(–0.9) mm; petals white, elliptic to linear, 0.4–0.5 × ca. 0.1 mm, claw absent; stamens 2, median; filaments 0.3–0.6 mm; anthers 0.1–0.2 mm. |
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. |
Fruiting pedicels | divaricate to horizontal, straight slightly recurved, (terete), 1.4–2.5(–4) × 0.15–2 mm, glabrous or sparsely pubescent adaxially. |
divaricate to horizontal, straight or recurved to somewhat sigmoid, (terete), 3.5–8(–11) × 0.2 mm, glabrous or puberulent adaxially. |
Fruits | schizocarpic, didymous, 1.3–1.7 × 2–2.5 mm, apically not winged, apical notch 0.2–0.4 mm deep; valves thick, rugose, strongly veined, glabrous; style absent or obsolete, included in apical notch. |
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. |
Seeds | ovate, 1–1.2 × 0.7–0.8 mm. |
ovate, 1.5–1.8(–2) × 0.9–1.2(–1.5) mm. |
2n | = 32. |
= 32. |
Lepidium didymum |
Lepidium alyssoides |
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Phenology | Flowering Mar–Jul. | Flowering May–Jul. |
Habitat | Roadsides, waste areas, lawns, pastures, fields, gardens, disturbed areas | Pinyon-juniper or sagebrush communities, prairies, grasslands, sandstone outcrops, gypsum flats, sand dunes, dry flats and river bottoms, gravelly roadsides |
Elevation | 0-1000 m (0-3300 ft) | 1200-2800 m (3900-9200 ft) |
Distribution |
AL; AR; AZ; CA; CT; FL; GA; LA; MA; MD; ME; MO; MS; NC; NJ; NY; OH; OR; PA; SC; TN; TX; VA; WI; WV; BC; NB; NF; NS; QC; South America [Introduced in North America; introduced also in Mexico (Sinaloa), Central America (Honduras), Europe, Asia, s Africa, Australia]
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AZ; CO; NM; NV; TX; UT; WY; Mexico (Chihuahua, Coahuila, Nuevo León, San Luis Potosí)
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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.) |
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Source | FNA vol. 7, p. 580. | FNA vol. 7, p. 575. |
Parent taxa | Brassicaceae > tribe Lepidieae > Lepidium | Brassicaceae > tribe Lepidieae > Lepidium |
Sibling taxa | ||
Synonyms | Carara didyma, Coronopus didymus, Senebiera didyma, Senebiera incisa, Senebiera pinnatifida | 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 |
Name authority | Linnaeus: Syst. Nat. ed. 12, 2: 433. (1767): Mant Pl. 1: 92. (1767) | A. Gray: Mem. Amer. Acad. Arts, n. s. 4: 10. (1849) |
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