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feather-leaf pepper-weed, wayside pepper grass

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

Habit Annuals; puberulent. Annuals; (fetid); glabrous or pilose.
Stems

simple from base, erect, (paniculately) branched beyond base or distally, 2–6 dm.

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

Basal leaves

(soon withered, often before anthesis);

not rosulate;

blade dentate to pinnatifid.

(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).

Cauline leaves

shortly petiolate to subsessile;

blade narrowly oblanceolate to linear, 1–3.3 cm × 1–4 mm, base attenuate, not auriculate, margins entire.

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.

Racemes

(often paniculate), considerably elongated in fruit;

rachis glabrous or puberulent, trichomes straight, cylindrical.

elongated in fruit;

rachis glabrous or pubescent, trichomes straight, cylindrical.

Flowers

sepals oblong, 0.7–0.8 × 0.3–0.4 mm;

petals (rudimentary), white, linear, 0.4–0.6 × 0.05–0.1 mm, claw absent;

stamens 4, median and lateral;

filaments 0.6–0.8 mm;

anthers ca. 0.2 mm.

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.

Fruiting pedicels

divaricate-ascending to horizontal, straight, (terete), 2–3.5 × 0.1–0.15 mm, puberulent adaxially.

divaricate to horizontal, straight slightly recurved, (terete), 1.4–2.5(–4) × 0.15–2 mm, glabrous or sparsely pubescent adaxially.

Fruits

orbicular to broadly elliptic, 1.8–2 × 1.7–1.8 mm, apically not winged, apical notch 0.05–0.1 mm deep;

valves thin, smooth, not veined, sparsely pilose;

style ca. 0.1 mm, equaling apical notch.

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.

Seeds

oblong, 1–1.2 × 0.7–0.8 mm.

ovate, 1–1.2 × 0.7–0.8 mm.

2n

= 32.

Lepidium pinnatifidum

Lepidium didymum

Phenology Flowering May–Jun. Flowering Mar–Jul.
Habitat Waste places, disturbed sites Roadsides, waste areas, lawns, pastures, fields, gardens, disturbed areas
Elevation 0-600 m (0-2000 ft) 0-1000 m (0-3300 ft)
Distribution
from USDA
e Europe; w Asia [Introduced, Calif.]
[WildflowerSearch map]
[BONAP county map]
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]
Discussion

Lepidium pinnatifidum apparently has not become a serious weed of the Californian flora.

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

Source FNA vol. 7, p. 591. FNA vol. 7, p. 580.
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. didymum, 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. 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. 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
Synonyms Carara didyma, Coronopus didymus, Senebiera didyma, Senebiera incisa, Senebiera pinnatifida
Name authority Ledebour: Fl. Ross. 1: 206. (1841) Linnaeus: Syst. Nat. ed. 12, 2: 433. (1767): Mant Pl. 1: 92. (1767)
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