Lepidium juvencum

Detailed description

Tap-rooted, strongly pungent smelling, perennial herb. Growth habit open, straggly, up to 50 cm tall. Stems usually decumbent to sprawling, slender, flexible, sparse; mature stems woody, 100–1000 × 8–12 mm, often devoid of foliage on middle and lower parts of stems; new stems 100–400 × 3–4 mm, leafy, glabrous. Leaves glabrous, subcoriaceous, green, often undulate, rosette and stem leaves usually withering, variable in size and shape. Leaves of young and vigorous plants and stems: lamina 37–87 × 12–32 mm, elliptic, obovate or elliptic-oblanceolate; apex truncate to obtuse, usually with 2–3 prominent teeth and often appearing irregular; margin singly crenate, with 4–19 pairs of teeth; teeth up to 1.5 mm deep, not overlapping; base attenuate to cuneate, tapering to a distinct or indistinct petiole; petiole up to 23.0 × 2.0–5.0 mm, or sessile. Leaves of mature plants and cauline stems: lamina 10–60 × 3–21 mm, elliptic, elliptic-oblanceolate, obovate to elliptic-obovate; apex subacute, truncate or obtuse, usually with 2–3 prominent teeth and often appearing irregular; margin singly crenate in upper and/or lower half, with 4–19 pairs of teeth; teeth up to 1.3 mm deep, not overlapping; base attenuate to cuneate, tapering to distinct or indistinct petiole, or sessile. Inflorescence terminal and lateral, racemose, 10–60 mm long, rachis 1.0–1.3 mm diameter, glabrous; pedicels 4.0–6.0 mm long, erecto-patent, usually glabrous although lower pedicels occasionally sparsely hairy on adaxial surface. Flowers 4.0–5.0 mm diameter. Sepals 4, 1.3–1.5 mm long, saccate, overlapping at base, green, apex obtuse, margin white, shape dimorphic; lateral sepals broad, 1.1–1.5 mm diameter, orbicular, abaxial surface often hairy, hairs 0.1–0.5 mm long; median sepals narrow, 0.9–1.2 mm diameter, broadly elliptic, glabrous. Petals white, 2.0–2.4 × 1.1–1.5 mm, spreading, claw 0.6–1.0 mm long; limb broadly elliptic to orbicular, apex obtuse to rounded. Stamens 4(–5); filaments 1.4–1.7 mm long, base 0.3–0.5 mm diameter, equal; anthers 0.3–0.4 mm long. Ovary 1.0–1.5 × 0.9–1.4 mm, broadly ovate to broadly elliptic, green to green-brown, apex usually with shoulders; style 0.15–0.25 mm long, cylindrical; stigma 0.3–0.5 mm diameter. Nectaries 4, 0.2–0.3 × c. 0.1 mm, oblong-obovate, green. Silicles cartilaginous when fresh, coriaceous when dry, 3.1–4.2 × 2.5–3.5 mm, elliptic-rhomboid to orbicular-rhomboid, valves light brown, glabrous, apex shallowly notched, not winged; style 0.2–0.3 mm long, exserted. Seeds 1.6–1.8 × 0.9–1.3 mm, narrowly ovoid, brown to orange-brown, not winged.