Lepidium didymum |
Lepidium flavum |
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lesser pepper-grass, lesser swine-cress, lesser wart-cress |
yellow pepper grass, yellow pepperweed |
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Habit | Annuals; (fetid); glabrous or pilose. | Annuals; glabrous. |
Stems | few to several from base, erect to ascending or decumbent, branched distally, 1–4.5(–7) dm. |
few to several from base, prostrate or decumbent, branched, (0.2–)0.4–3(–4.6) 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 (0.3–)0.6–2.5(–3.2) cm; blade spatulate to oblanceolate or linear, pinnatifid or lobed (lobes 3–9 pairs, ovate to oblong), (0.7–)1.3–5.2(–6) cm × 3–8 mm, margins (of lobes) 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. |
petioles 0.1–0.5 cm; blade obovate to spatulate or oblanceolate, (0.6–)1–1.8(–2.3) cm × 2–8(–14) mm, base attenuate-cuneate, not auriculate, margins dentate-sinuate to crenate orentire. |
Racemes | elongated in fruit; rachis glabrous or pubescent, trichomes straight, cylindrical. |
(corymbose to subcapitate), slightly elongated in fruit; rachis 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 obovate-oblong, 1–2 × 0.6–1 mm; petals yellow (rarely creamy white at early anthesis), spatulate, (1.8–)2–2.8(–3) × 0.6–1 mm, claw 0.5–1 mm; stamens 6; filaments (median pairs) 1.2–2 mm, (glabrous); anthers 0.4–0.5 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 slightly sigmoid, (terete), (2.7–)3–4.4(–5) × 0.2–0.3 mm, glabrous. |
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. |
usually narrowly to broadly ovate, rarely suborbicular, (2.2–)2.5–3.8(–4.2) × (1.6–)2.2 3.2(–3.5) mm, apically divergently winged, apical notch 0.2–0.6 mm deep; valves thin, smooth, moderately reticulate-veined, usually glabrous, rarely pubescent; style 0.7–1.6 mm, exserted beyond apical notch. |
Seeds | ovate, 1–1.2 × 0.7–0.8 mm. |
ovate, 1–1.6 × 0.6–0.9 mm. |
2n | = 32. |
= 32. |
Lepidium didymum |
Lepidium flavum |
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Phenology | Flowering Mar–Jul. | Flowering Mar–Jun. |
Habitat | Roadsides, waste areas, lawns, pastures, fields, gardens, disturbed areas | Sagebrush communities, open mesas, sandy flats and deserts, alluvial fans, dry valley floors, floodplains, washes, alkaline flats, roadsides, playa margins |
Elevation | 0-1000 m (0-3300 ft) | 600-1600 m (2000-5200 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; NV; Mexico (Baja California)
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Discussion | The slightly smaller-fruited form of Lepidium flavum, recognized by C. L. Hitchcock (1936) and R. C. Rollins (1993) as var. felipense, does not merit recognition. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 7, p. 580. | FNA vol. 7, p. 582. |
Parent taxa | Brassicaceae > tribe Lepidieae > Lepidium | Brassicaceae > tribe Lepidieae > Lepidium |
Sibling taxa | ||
Synonyms | Carara didyma, Coronopus didymus, Senebiera didyma, Senebiera incisa, Senebiera pinnatifida | L. flavum var. apterum, L. flavum var. felipense, Nasturtium flavum, Sprengeria flava, Sprengeria minuscula, Sprengeria watsoniana |
Name authority | Linnaeus: Syst. Nat. ed. 12, 2: 433. (1767): Mant Pl. 1: 92. (1767) | Torrey: in War Department [U.S.], Pacif. Railr. Rep. 4(5): 67. (1857) |
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