Prostrate biennial or perennial, branches slender (under 5 mm diam.), 30–70 cm long. Leaves 1–3-pinnate, lower leaves 5–20 cm long, those opposite inflorescence 2–15 cm long; primary leaflets 3–7(–9), sometimes 1–2-ternate; petiole as long or longer than lamina. Umbels 3.5–7 cm diam., sessile or rarely with peduncle to 20 mm long; rays 2–15, 0.5–5.5 cm long; umbellules 4–15-flowered; pedicels to 5 mm long. Petals ovate, white with yellow-brown midrib. Fruit obovate to orbicular, c. 1.5–2.5 mm long, the furrows between ribs almost concealed. Flowers Dec.–Mar.
Brid, CVU, DunT, EGL, GipP, Glep, Gold, GGr, HNF, HSF, MonT, NIS, OtP, OtR, Strz, VVP, WaP, WPro, Wim. A widespread species occurring across southern Australia, New Zealand, and possibly South America, usually in coastal situations on sand dunes, cliff faces or near estuaries and saline lakes, but also occasionally beside fresh-water streams. The two Victorian varieties are largely sympatric and there are many intermediate populations.
There are 3 named (and one apparently unnamed, from W.A.) subspecies of Apium prostratum. Only the typical subspecies occurs in Victoria, represented by two varieties. The subspecific epithet is not included in the names used here.
The occurrence of A. prostratum in South America is uncertain. The commonly assumed synonymy of A. prostratum and A. australe Thouars (generally a more robust plant, type from remote Tristan da Cunha, between South America and Africa) requires confirmation.
|Bioregion||Occurrence status||Establishment means|
|Victorian Volcanic Plain||present||native|
|Central Victorian Uplands||present||native|
|Northern Inland Slopes||present||native|
|East Gippsland Lowlands||present||native|
|New South Wales|
|Australian Capital Territory|