Cardamine flexuosa With.

Annual or biennial herb, single rosette or with short lateral branches. Leaves up to 120 mm long, pinnatisect, not rosulate, withering in fruit; lamina 4.0–105.0 × 2.5–60.0 mm, green, membranous, glabrous to sparsely hairy on adaxial surface and margin, glabrous on abaxial surface and petiole; hairs 0.2–0.4 mm long, spreading to patent; petiole up to 35 mm long. Terminal pinna 2.0–24.0 × 2.0–27.0 mm, simple, orbicular, orbicular-reniform to broadly orbicular-reniform, repand; margin entire, sometimes shallowly and irregularly lobed, with 2–4 usually ± distinct hydathodes; apex obtuse, usually with a ± distinct hydathode; base weakly cordate, truncate or obtuse. Lateral pinnae 2–10, 1.0–23.0 × 1.0–19.0 mm, orbicular, orbicular-rhomboid, to broadly elliptic; margin entire, occasionally weakly lobed, with 2–4 usually ± distinct hydathodes; apex obtuse, usually with a ± distinct hydathode; base obtuse to cuneate, often oblique; petiolule 0.2–14.0 mm long, often appearing ± sessile. Cauline leaves similar to rosette leaves but becoming narrower, smaller, and deeper lobed to toothed; pinnae broadly elliptic to elliptic-rhomboid, bases cuneate to obtuse; terminal pinna up to 30.0 × 16.0 mm, lateral pinnae up to 24.0 × 14.0 mm; petiolules sessile or up to 10.0 mm long. Inflorescence racemose, with lateral racemes, each raceme 3–20-flowered, erect, ascending or decumbent, flexuous or straight; peduncle up to 200 mm long, 1.0–2.5 mm diam. At base, erect, sparsely hairy to glabrous. Pedicels 3.5–17.0 mm long, 0.3–0.6 mm diam., usually glabrous or rarely sparsely hairy, dorsi-ventrally compressed, at fruiting divaricate or ascending; axils with hydathode and 1–2 patent hairs. Sepals 1.5–3.5 × 0.7–1.4 mm, elliptic-oblong, saccate, green, glabrous or sparsely hairy, margin usually white and membranous, apex obtuse, base truncate. Petals 4; 2.5–4.0 × 1.0–1.7 mm, white, limb obovate; apex obtuse; base cuneate, tapering to a 0.8–1.0 mm long claw. Stamens 6(–4); median filaments 4, 2.3–2.4 mm long; lateral filaments 2, 2.6–2.7 mm long; anthers 0.3–0.5 mm long, pale yellow, when dehiscent held at a similar height to or slightly below the stigma. Ovary 2.5–2.9 mm long, 0.4–0.5 mm diam., ± terete, green, glabrous; ovules 18–40; style c. 0.1 mm long, ± terete; stigma 0.5–0.6 mm diam., white. Siliques 12.0–28.0 × 1.0–1.5 mm, glabrous, style 0.3–1.0 mm long; valves green at maturity and when dehiscent; replum 0.3–0.5 mm wide. Seeds 0.8–1.0 mm long, 0.7–0.9 mm wide, 0.3–0.4 mm thick, oblong-orbicular to broadly oblong, light green to light yellow-brown; wing absent.

Cardamine flexuosa predominantly occurs in damp or wet and often shaded sites, where it can be found as a garden weed, within or on the margins of disturbed or open indigenous forest and scrub, in wasteland and exotic plantations, along the margins of stream banks, and at the edge of road cuttings and tracks.

The specimen (CHR 70259) supporting the first record was collected from Marokopa River, near Te Anga, Kāwhia County (South Auckland), in 1947 (Healy 1957; see also Garnock-Jones 1979). Healy (1957) provides details of additional specimens collected from other parts of the North Island and also the first South Island collection from Dunedin in 1951 (CHR 71732).

Flowering January–December; Fruiting January–December.