Apium insulare

Erect biennial to c. 20 cm high, stems ribbed, 8–10 mm wide. Leaves 1–2-pinnate, upper leaves much smaller than lower, lamina to 15(–30) cm long; leaflets 5–15(–23), elliptic to obovate, 2–8.5 cm long, each variously lobed or toothed; petiole usually shorter than lamina. Umbels 5–8 cm diam., thickly pedunculate, peduncle 4–8.5 cm long; rays 10–25, c. equal, to 5 cm long; umbellules c. 15–25-flowered; pedicels to 7 mm long. Petals c. 1 mm long, white, sometimes with a yellow midrib. Fruit broad-ovoid, c. 1.5–2.5 mm long; mericarps almost covered by the 5 corky, yellow ribs. Flowers Oct.–Feb.