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lesser pepper-grass, lesser swine-cress, lesser wart-cress

heart-pod hoary-cress, heart-pod pepperweed, hoary cress, hoary pepperwort, whitetop

Habit Annuals; (fetid); glabrous or pilose. Perennials; (rhizomatous); hirsute or glabrate.
Stems

few to several from base, erect to ascending or decumbent, branched distally, 1–4.5(–7) dm.

often simple from base, erect or decumbent basally, branched (several) distally, (0.8–)2–6.5(–9) 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).

(early withered);

not rosulate;

petiole 1–4 cm;

blade obovate, spatulate, or ovate, (1.5–)3–10(–15) cm × 10–40 mm, margins sinuate to dentate or 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 ovate, elliptic, oblong, or lanceolate, oblanceolate, or obovate, (1–)3–9(–15) cm × (5–)10–20(–50) mm, base sagittate-amplexicaul or auriculate, margins dentate or entire, (surfaces pubescent or glabrous).

Racemes

elongated in fruit;

rachis glabrous or pubescent, trichomes straight, cylindrical.

(corymbose panicles), slightly or considerably elongated in fruit;

rachis glabrous or puberulent, trichomes straight or curved, 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, 1.5–2.5 × 0.7–1.2 mm;

petals white, obovate, (2.5–)3–4(–4.5) × (1–)1.3–2(–2.2) mm, claw 1–1.7 mm;

stamens 6;

filaments 2–3 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.

ascending to horizontal, straight, (terete), 5–10(–15) × 0.2–0.3 mm, glabrous or sparsely 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.

(indehiscent), cordate to subreniform, (2–)2.5–3.7(–4.3) × (3.2–)3.7–5(–5.6) mm, apically (obtuse to subacute), not winged, apical notch absent;

valves thin, smooth, reticulate-veined, glabrous;

style (0.6–)1–1.8(–2) mm.

Seeds

ovate, 1–1.2 × 0.7–0.8 mm.

ovate, 1.5–2.3 × 1–1.3 mm.

2n

= 32.

= 32, 64.

Lepidium didymum

Lepidium draba

Phenology Flowering Mar–Jul. Flowering Apr–Aug.
Habitat Roadsides, waste areas, lawns, pastures, fields, gardens, disturbed areas Mountain slopes, roadsides, fields, agricultural lands, stream sides, disturbed grounds, pastures, waste areas
Elevation 0-1000 m (0-3300 ft) 0-3300 m (0-10800 ft)
Distribution
from FNA
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]
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; CT; DC; IA; ID; IL; IN; KS; MA; MD; MI; MN; MO; MT; ND; NE; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SD; UT; WA; WY; AB; BC; MB; NS; ON; SK; s Europe; sw Asia [Introduced in North America; introduced also in Mexico (Distrito Federal), South America, s Africa, Australia]
[WildflowerSearch map]
[BONAP county map]
Discussion

Although Lepidium draba is poorly established and known from old collections in the eastern part of the United States, it has become a noxious weed in several western states.

Lepidium draba and its nearest relatives, L. appelianum and L. chalepense, form a monophyletic clade most closely related to L. campestre (K. Mummenhoff et al. 2001). A. Thellung (1906) and C. L. Hitchcock (1936) correctly placed L. draba in Lepidium, as did Linnaeus. The recognition of the first three species in Cardaria and the maintenance of their nearest relative, L. campestre, in Lepidium do not make any sense on both phylogenetic and taxonomic grounds.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 7, p. 580. FNA vol. 7, p. 581.
Parent taxa Brassicaceae > tribe Lepidieae > Lepidium Brassicaceae > tribe Lepidieae > Lepidium
Sibling taxa
L. acutidens, L. alyssoides, L. appelianum, L. austrinum, L. barnebyanum, L. campestre, L. chalepense, L. coronopus, L. crenatum, L. davisii, L. densiflorum, L. dictyotum, L. draba, L. eastwoodiae, L. flavum, L. fremontii, L. heterophyllum, L. huberi, L. integrifolium, L. jaredii, L. lasiocarpum, L. latifolium, L. latipes, L. montanum, L. nanum, L. nitidum, L. oblongum, L. ostleri, L. oxycarpum, L. papilliferum, L. paysonii, L. perfoliatum, L. pinnatifidum, L. ramosissimum, L. ruderale, L. sativum, L. sordidum, L. strictum, L. thurberi, L. tiehmii, L. virginicum
L. acutidens, L. alyssoides, L. appelianum, L. austrinum, L. barnebyanum, L. campestre, L. chalepense, L. coronopus, L. crenatum, L. davisii, L. densiflorum, L. dictyotum, L. didymum, L. eastwoodiae, L. flavum, L. fremontii, L. heterophyllum, L. huberi, L. integrifolium, L. jaredii, L. lasiocarpum, L. latifolium, L. latipes, L. montanum, L. nanum, L. nitidum, L. oblongum, L. ostleri, L. oxycarpum, L. papilliferum, L. paysonii, L. perfoliatum, L. pinnatifidum, L. ramosissimum, L. ruderale, L. sativum, L. sordidum, L. strictum, L. thurberi, L. tiehmii, L. virginicum
Synonyms Carara didyma, Coronopus didymus, Senebiera didyma, Senebiera incisa, Senebiera pinnatifida Cardaria draba, Cochlearia draba, Nasturtium draba
Name authority Linnaeus: Syst. Nat. ed. 12, 2: 433. (1767): Mant Pl. 1: 92. (1767) Linnaeus: Sp. Pl. 2: 645. (1753)
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