Lepidium didymum |
Lepidium acutidens |
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lesser pepper-grass, lesser swine-cress, lesser wart-cress |
alkali pepperwort, alkali veiny pepper-grass, net pepper grass |
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Habit | Annuals; (fetid); glabrous or pilose. | Annuals; hirsute or 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, unbranched, (0.5–)0.8–3 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). |
(soon withered); not rosulate; petiole 1–4 cm; blade linear or pinnatisect, (2–)2.5–6.1(–7.2) cm × (0.5–)1–2(–3) mm, (lobes linear to narrowly oblong), 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. |
sessile; blade linear, 1.2–5.8 cm × 0.5–2(–3) mm, base attenuate, not auriculate, margins entire. |
Racemes | elongated in fruit; rachis glabrous or pubescent, trichomes straight, cylindrical. |
elongated, (dense or lax) in fruit; rachis puberulent or hirsute, 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 oblong to ovate, 0.7–1.1 × 0.2–0.6 mm; petals absent; stamens 4, median; filaments 0.5–1 mm; anthers ca. 0.1 mm. |
Fruiting pedicels | divaricate to horizontal, straight slightly recurved, (terete), 1.4–2.5(–4) × 0.15–2 mm, glabrous or sparsely pubescent adaxially. |
erect to slightly ascending, straight and appressed to rachis or distally slightly recurved, (strongly flattened), (2–)3–4.2 × 0.4–0.6 mm (width proximal to apex), 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 to ovate-oblong, (3–)4–6 × 2.5–3.5 mm, apically winged, apical notch (V-shaped), (0.8–)1–2 mm deep; valves thin, smooth, strongly reticulate-veined, usually glabrous, rarely pubescent; style absent or obsolete, included in apical notch. |
Seeds | ovate, 1–1.2 × 0.7–0.8 mm. |
ovate, 1.3–2 × 0.8–1.2 mm. |
2n | = 32. |
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Lepidium didymum |
Lepidium acutidens |
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Phenology | Flowering Mar–Jul. | Flowering Feb–Apr. |
Habitat | Roadsides, waste areas, lawns, pastures, fields, gardens, disturbed areas | Alkaline flats, gullies, or fields, saline vernal flats, grassy fields |
Elevation | 0-1000 m (0-3300 ft) | 0-400 m (0-1300 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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CA; OR; Mexico (Baja California)
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Discussion | Lepidium acutidens was treated by C. L. Hitchcock (1936) and R. C. Rollins (1993) as a variety of L. dictyotum. The differences in the fruits as well as the absence of intermediates between them, despite the overlap of their ranges in California, justify their recognition as independent species. (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. dictyotum var. acutidens, L. oxycarpum var. acutidens |
Name authority | Linnaeus: Syst. Nat. ed. 12, 2: 433. (1767): Mant Pl. 1: 92. (1767) | (A. Gray) Howell: Fl. N.W. Amer., 64. (1897) |
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