Lepidium panniforme

Detailed description

Tap-rooted, pungent-smelling, summer-green, perennial herb arising from stock rootstock 7.3–8(–10) mm diam. Growth habit, erect to suberect, loose to densely branched plants up to 1 m across. Stems ± persistent, sometimes dying down to rootstock over winter or in times of adversity; upright to spreading, bases often very stout, ± spherical, somewhat woody when mature 10–15 × 10–12 mm, comprised of numerous old leaf and stem bases, sometimes producing roots, new seasons grow erect to suberect, glabrous, sometimes with very sparse, appressed, caducous, silky 0.5–1 mm long, hairs near stem apices; at fruiting stems often devoid of foliage for much of length. Leaves glabrous, firmly fleshy to succulent, usually dark green to green, sometimes yellow-green. Rosette and stem leaves usually withering at fruiting but sometimes with a few long persistent. Petiole distinct, 20–35(–40) × 2–9 mm. Lamina oblanceolate, lanceolate, narrowly lanceolate (rarely spathulate), 50–100 × 10–30 mm; either deeply toothed and/or lacerate or with distal ⅔ to ⅓ deeply toothed and/or deeply lacerate, teeth in 10–18(–20) pairs, blunt to sharp, running to and including apex and usually extending beyond leaf outline, base cuneate to narrowly cuneate. Middle stems leaves usually with indistinct petioles, these 10–30 mm long; lamina narrowly linear-lanceolate to linear, often recurved to falcate from or near ½ to ⅓ of leaf length, 50–80(–120) × 3–6 mm; margins deeply lacerate and/or toothed, teeth usually prominent, often confined to the upper ⅔, in 12–18(–30) pairs, these running to and including the apex; lamina base tapered, very narrowly cuneate. Upper stem leaves with or without a distinct petiole, petiole if present 40–60 mm, linear to linear-spathulate, occasionally narrowly lanceolate, usually toothed and/or lacerate, patent or recurved and/or falcate for upper ½ of leaf length, 30–50(–100) × 2.0–3.0(–30) mm. Racemes (5–)10–15 mm long, terminal and axillary; rachis glabrous; pedicels glabrous, erecto-patent, 2–5(–8) mm long at fruiting. Flowers c.0.4–0.8(–1.0) mm diam. Sepals glabrous or finely pubescent, or with both states within the one flower, green, broadly ovate to oval, c.0.6–1.0 × 0.6–1.2 mm, with pale-green to white thickened margin, apex broadly obtuse. Petals white, 1.5–2.0 × 0.3–0.8(–1) mm, erecto-patent to somewhat spreading, clawed; limb narrowly obovate, apex obtuse, occasionally emarginated. Stamens (2–)4, equal. Nectaries 2, subulate, 0.35 mm long. Silicles cartilaginous when fresh, coriaceous when dry, orbicular, orbicular-rhomboid (2.5–)3.0–3.5 × (1.5–)1.8–2.5(–3.3), slightly winged in upper ⅓, apex minutely notched, based obtuse to ± cordate, valves glabrous, dried surface often distinctly reticulate; style 0.1–0.2(–0.3) mm long, free from the narrow wing, exceeding the shallow notch; stigma 0.2–0.3 mm diam., capitate. Seeds 2, narrowly ovoid, brown, red-brown to orange-brown, not winged, 1.25–1.3 × 0.35–0.60 mm.