Contr. U.S. Natl Herb. 4: 115 (1893) APNI
Taxonomic status:Accepted
Occurrence status:Present
Establishment means:Uncertain
Threat status:Victoria: data deficient (k)
Aquatic or semi-aquatic herb 30–100 cm high; stems branched, hollow, striate to furrowed. Emergent leaves once-pinnate, submerged leaves 3–4-pinnate, lamina 12–40 cm long, 1.5–12 cm wide; leaflets 15–21, oblong-lanceolate or c. ovate, 8–56 mm long, 4–35 mm wide, toothed, sessile. Umbels 3–6 cm diam.; peduncles 3–8 cm long; bracts lanceolate, uneven, 10–20 mm long; rays 6–20, unequal, to 20 mm long; umbellules 6–12 mm diam., 9–22-flowered, bracteoles linear or lanceolate, 2–3.5 mm long; pedicels to 5 mm long. Petals c. 1 mm long, white. Fruit 1.5–2 mm long.
HSF, *EGL, *EGU, *GipP, *VVP, *WaP, *WPro. Also naturalised WA, SA, Qld, NSW, Tas. Native from Europe to central Asia, and North America. Occurring in lowland, often near-coastal, swamps and streams in southern Victoria. Flowering Dec.-Mar.
This species is now widely treated as a natualised alien in Australia but was once regarded as an indigenous variety (univittatum) of the European Sium latifolium. It is regarded as of uncertain origin in Victoria as it has been recorded mostly from high-quality, largely weed-free watercourses.
Often confused with Helosciadium nodiflorum which has 0–2 bracts at the base of the umbels.
| Bioregion | Occurrence status | Establishment means | |
|---|---|---|---|
| Victorian Volcanic Plain | present | introduced | |
| Gippsland Plain | present | introduced | |
| Warrnambool Plain | present | introduced | |
| East Gippsland Lowlands | present | introduced | |
| East Gippsland Uplands | present | introduced | |
| Wilsons Promontory | present | introduced | |
| Highlands-Southern Fall | present | uncertain |
| State |
|---|
| Western Australia |
| South Australia |
| Queensland |
| New South Wales |
| Australian Capital Territory |
| Victoria |
