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

mesa pepperwort

Habit Annuals; (fetid); glabrous or pilose. Perennials or subshrubs; (woody base often aboveground); glabrous or minutely 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, branched throughout, (0.7–)1–4.8(–6.1) 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).

often not rosulate;

petiole 1–6 cm;

blade pinnately lobed, (1–)1.5–8(–11) cm × (5–)10–35 mm, margins (of lobes) entire or denticulate.

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, (0.8–)1.3–7(–9.5) cm × (0.7–)1–2(–3) mm, base attenuate, not auriculate, margins entire.

Racemes

elongated in fruit;

rachis glabrous or pubescent, trichomes straight, cylindrical.

elongated in fruit;

rachis puberulent or 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 ovate to oblong, 1–2 × 0.8–1 mm;

petals white, suborbicular, 2–3 × 1–2 mm, claw 0.5–1.5 mm;

stamens 6;

filaments 1.5–2 mm, (glabrous);

anthers 0.2–0.4 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 recurved to somewhat sigmoid, (terete), 3.5–8(–11) × 0.2 mm, glabrous or 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.

broadly ovate, 2–3.7(–4.3) × (1.5–)1.8–2.9(–3.4) mm, apically winged, apical notch 0.1–0.3(–0.4) mm deep;

valves thin, smooth, not veined, glabrous;

style 0.2–0.6 mm, exserted beyond apical notch.

Seeds

ovate, 1–1.2 × 0.7–0.8 mm.

ovate, 1.5–1.8(–2) × 0.9–1.2(–1.5) mm.

2n

= 32.

= 32.

Lepidium didymum

Lepidium alyssoides

Phenology Flowering Mar–Jul. Flowering May–Jul.
Habitat Roadsides, waste areas, lawns, pastures, fields, gardens, disturbed areas Pinyon-juniper or sagebrush communities, prairies, grasslands, sandstone outcrops, gypsum flats, sand dunes, dry flats and river bottoms, gravelly roadsides
Elevation 0-1000 m (0-3300 ft) 1200-2800 m (3900-9200 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; CO; NM; NV; TX; UT; WY; Mexico (Chihuahua, Coahuila, Nuevo León, San Luis Potosí)
[WildflowerSearch map]
[BONAP county map]
Discussion

Of the five varieties of Lepidium alyssoides recognized by R. C. Rollins (1993), one (var. mexicanum Rollins) is a short-tufted form of the species restricted to Mexico that does not seem to merit recognition, another (var. junceum) is a glabrescent form of the type variety, a third (var. eastwoodiae) is treated below as a distinct species, and the fourth (var. angustifolium) is included here within L. alyssoides.

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

Source FNA vol. 7, p. 580. FNA vol. 7, p. 575.
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. 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. 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 L. alyssoides var. angustifolium, L. alyssoides var. junceum, L. alyssoides var. minus, L. alyssoides var. polycarpum, L. alyssoides var. streptocarpum, L. montanum subsp. alyssoides, L. montanum var. alyssoides, L. montanum subsp. angustifolium, L. montanum var. angustifolium, L. tortum
Name authority Linnaeus: Syst. Nat. ed. 12, 2: 433. (1767): Mant Pl. 1: 92. (1767) A. Gray: Mem. Amer. Acad. Arts, n. s. 4: 10. (1849)
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