Apium nodiflorum (L.) Lag.

Weak, trailing or ascending perennial, glabrous, rooting at the lower nodes with clusters of white rootlets, 11–80(–100) cm.. Stems finely striate, fleshy and fistular, ± 0.3–1.6 cm. in diameter, simple or branched.. Lower and middle stem leaves with the lamina ovate to oblong in outline, 4–40 cm. long, pinnate with 2–6 pairs of sessile leaflets; leaflets lanceolate to ovate, (5–)9–55(–75) × (3.5–)5–20(–40) mm., regularly or irregularly dentate, the terminal in particular sometimes ± lobed; petiole 1.5–12 cm.; sheaths 15–35(–50) mm., narrowly oblong, striate, membranous-margined; upper leaves sessile, shorter, with fewer leaflets.. Umbels leaf-opposed, sessile or shortly (to ± 4 mm.) pedunculate, with 5–10 unequal rays ± 8–30 mm. long; involucre commonly absent, occasionally of up to 3 narrowly lanceolate bracts up to ± 3 mm. long, especially in pedunculate umbels; flowers ± 12–20 in each partial umbel, pedicels (0–)1.5–5 mm.; involucel conspicuous, of 5–7 lanceolate, nervose, acute, pale-margined bracteoles 3–6 mm. long.. Calyx-teeth obsolete.. Petals ± 0.75 mm., white.. Fruit ovoid to almost round, laterally compressed, 1.25–2 mm. long, with narrow, prominent, pale primary ribs; stylopodia small, flat; styles slender, ± twice as long as the stylopodia.

It is a Mediterranean climate plant. It grows in wet meadows and near rivers. It is usually in chalk and limestone areas. It cannot grow in shade.

The leaves are used raw in salads. They are also boiled and used in soups and stews. The seeds can be sprouted and eaten in salads. The seeds are also ground and used as a mustard. The young stem are eaten boiled, fried or raw in salads.