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mesa pepperwort

purple-anther field pepper-weed, purple-anther pepperweed, Smith's pepper-grass, Smith's pepperweed, Smith's pepperwort, variable leaf pepperwort, variable-leaf pepperweed

Habit Perennials or subshrubs; (woody base often aboveground); glabrous or minutely puberulent. Perennials; (caudex branched); hirsute.
Stems

few to several from base, erect to ascending, branched throughout, (0.7–)1–4.8(–6.1) dm.

branched from base, erect to ascending, often decumbent basally, unbranched or branched (few) distally, 1–5 dm.

Basal leaves

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.

rosulate;

petiole 1–6.2 cm;

blade oblanceolate or oblong-elliptic, 1–4.5 cm × 4–14 mm, margins entire, repand, or denticulate.

Cauline leaves

sessile;

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

sessile;

blade oblong to deltate-lanceolate, 1–3.5 cm × 3–8 mm, base sagittate or auriculate, margins dentate to denticulate.

Racemes

elongated in fruit;

rachis puberulent or glabrous.

much-elongated in fruit;

rachis hirsute, trichomes spreading, straight.

Flowers

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.

sepals oblong, 1.6–2.2 × 0.6–1.1 mm;

petals white, spatulate, 1.8–2.8 × 0.8–1.4 mm, claw 1–2 mm;

stamens 6;

filaments 1.8–2.6 mm, (glabrous);

anthers 0.4–0.5 mm.

Fruiting pedicels

divaricate to horizontal, straight or recurved to somewhat sigmoid, (terete), 3.5–8(–11) × 0.2 mm, glabrous or puberulent adaxially.

horizontal, straight or slightly recurved, (terete), 2.8–5 × 0.3–0.4 mm, hirsute.

Fruits

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.

broadly oblong to ovate, 4–5.5 × 3.5–4 mm, (curved adaxially), apically broadly winged, apical notch 0.2–0.3 mm deep;

valves thin, often not papillate, not veined;

style (0.6–)1–1.5 mm, well-exserted beyond apical notch.

Seeds

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

(dark brown), ovoid, 1.8–2.2 × 1–1.2 mm.

2n

= 32.

= 48.

Lepidium alyssoides

Lepidium heterophyllum

Phenology Flowering May–Jul. Flowering May–Jun.
Habitat Pinyon-juniper or sagebrush communities, prairies, grasslands, sandstone outcrops, gypsum flats, sand dunes, dry flats and river bottoms, gravelly roadsides Gravel mounds, roadsides, abandoned fields, waste grounds, disturbed sites, gardens, hillsides
Elevation 1200-2800 m (3900-9200 ft) 0-300 m (0-1000 ft)
Distribution
from FNA
AZ; CO; NM; NV; TX; UT; WY; Mexico (Chihuahua, Coahuila, Nuevo León, San Luis Potosí)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; CO; MA; ME; NY; OR; PA; WA; BC; NF; Europe [Introduced in North America]
[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.)

The records from Maine and Massachusetts are based on old collections, and it is not known if Lepidium heterophyllum has become established as part of the weedy flora of those states.

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

Source FNA vol. 7, p. 575. FNA vol. 7, p. 582.
Parent taxa Brassicaceae > tribe Lepidieae > Lepidium Brassicaceae > tribe Lepidieae > Lepidium
Sibling taxa
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
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. 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 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 A. Gray: Mem. Amer. Acad. Arts, n. s. 4: 10. (1849) Bentham: Cat. Pl. Pyrénées, 95. (1826)
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