Lepidium perfoliatum
Sp. Pl. 2: 643. 1753.
Annuals or biennials; (glaucous), glabrous or sparsely pubescent proximally. Stems simple from base, erect, branched distally, (0.7–)1.5–4.3(–5.6) dm. Basal leaves rosulate; petiole (0.5–)1–2(–4) cm; blade 2- or 3-pinnatifid or pinnatisect (lobes linear to oblong), (1–)3–8(–15) cm, margins entire. Cauline leaves sessile; blade ovate to cordate or suborbicular, (0.5–)1–3(–4) cm × (5–)10–25(–35) mm, base deeply cordate-amplexicaul, not auriculate, margins entire. Racemes considerably elongated in fruit; rachis glabrous. Fruiting pedicels divaricate-ascending to horizontal, straight, (terete), 3–6(–7) × 0.2–0.3 mm, glabrous. Flowers: sepals oblong, 0.8–1(–1.3) × 0.5–0.8 mm; petals pale yellow, narrowly spatulate, 1–1.5(–1.9) × 0.2–0.5 mm, claw 0.5–1 mm; stamens 6; filaments 0.6–0.9 mm, (glabrous); anthers 0.1–0.2 mm. Fruits orbicular to rhombic or broadly obovate, 3–4.5(–5) × 3–4.1 mm, apically winged, apical notch 0.1–0.3 mm deep; valves thin, smooth, not or obscurely veined, glabrous; style 0.1–0.4 mm, subequaling or slightly exserted beyond apical notch. Seeds (dark brown), ovate, 1.6–2(–2.3) × 1.2–1.4 mm. 2n = 16.
Phenology: Flowering Mar–Jun.
Habitat: Waste places, dry sandy slopes, pinyon-juniper woodlands, sagebrush flats, open deserts, roadsides, pastures, meadows, open grasslands, alkaline flats and sinks, fields, disturbed sites
Elevation: 0-2500 m
Distribution
Alta., B.C., Man., Ont., Sask., Ariz., Ark., Calif., Colo., Conn., Ga., Idaho, Ind., Iowa, Kans., Maine, Mass., Mich., Miss., Mo., Mont., Nebr., Nev., N.Mex., N.Y., N.C., Ohio, Okla., Oreg., Pa., S.Dak., Tenn., Utah, Wash., Wis., Wyo., Europe, Asia, n Africa, introduced also in Mexico (Baja California), South America (Argentina), Australia.
Discussion
Selected References
None.