Lepidium didymum |
Lepidium nanum |
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lesser pepper-grass, lesser swine-cress, lesser wart-cress |
dwarf pepperweed |
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Habit | Annuals; (fetid); glabrous or pilose. | Perennials; (forming pincushion-like, pulvinate mounds, caudex woody, to 1.5 cm diam., buried, much-branched, covered with persistent leaves); puberulent. |
Stems | few to several from base, erect to ascending or decumbent, branched distally, 1–4.5(–7) dm. |
simple from base (caudex branches), erect to ascending, unbranched distally, 0.05–0.2 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). |
rosulate; petiole undifferentiated; blade obovate, 2.5–5 cm × 15–25(–35) mm, margins entire, (ciliolate), apex deeply 3-lobed (lobes ovate to suborbicular, margins entire). |
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. |
absent. |
Racemes | elongated in fruit; rachis glabrous or pubescent, trichomes straight, cylindrical. |
slightly elongated in fruit, (2–7-fruited); rachis puberulent, trichomes straight, cylindrical. |
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 (tardily deciduous), obovate, 1.3–4 × 0.8–1.1 mm; petals pale yellow or creamy white, spatulate, 1.8–2.9 × 0.8–1.2 mm, claw 0.8–1.1 mm; stamens 6; filaments 1.4–2 mm, (glabrous); anthers 1.4–2 mm. |
Fruiting pedicels | divaricate to horizontal, straight slightly recurved, (terete), 1.4–2.5(–4) × 0.15–2 mm, glabrous or sparsely pubescent adaxially. |
suberect to ascending, often straight, (terete), 2–4.5 × 0.2–0.3 mm, puberulent throughout. |
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. |
ovate, 2–4.2 × 1.5–3 mm, often apically winged, apical notch 0.1–0.2 mm deep; valves thin, smooth, not veined, glabrous; style (0.4–)0.6–1(–1.2) mm, exserted beyond apical notch. |
Seeds | ovate, 1–1.2 × 0.7–0.8 mm. |
oblong, 1–2 × 0.8–1 mm. |
2n | = 32. |
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Lepidium didymum |
Lepidium nanum |
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Phenology | Flowering Mar–Jul. | Flowering May–Jun. |
Habitat | Roadsides, waste areas, lawns, pastures, fields, gardens, disturbed areas | Gypsum knolls, tufa mounds around hotsprings, quartzite gravel, barren areas with shale and chalky soil, gravelly hillsides, white calcareous soils |
Elevation | 0-1000 m (0-3300 ft) | 1500-2200 m (4900-7200 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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NV; UT |
Discussion | Lepidium nanum is most common in Nevada and is known in Utah from collections in Tooele County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 7, p. 580. | FNA vol. 7, p. 587. |
Parent taxa | Brassicaceae > tribe Lepidieae > Lepidium | Brassicaceae > tribe Lepidieae > Lepidium |
Sibling taxa | ||
Synonyms | Carara didyma, Coronopus didymus, Senebiera didyma, Senebiera incisa, Senebiera pinnatifida | |
Name authority | Linnaeus: Syst. Nat. ed. 12, 2: 433. (1767): Mant Pl. 1: 92. (1767) | S. Watson: Botany (Fortieth Parallel), 30, plate 4, figs. 5–7. (1871) |
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