Myriophyllum porcatum Orchard

Ridged Water-milfoil

Brunonia 4: 59 (1981) APNI

Taxonomic status:Accepted

Occurrence status:Endemic

Establishment means:Native

Threat status:EPBC: vulnerable (VU); Victoria: vulnerable (v); listed in Flora and Fauna Guarantee Act 1988

Annual aquatic herb; stems 25–40 cm long, mostly 1–3 mm diam., rooting mainly at the base, emergent parts sparingly branched. Leaves dimorphic; submerged leaves in whorls of 4 or 5, broadly ovate, mostly 11–16 mm long, pectinate, with 10–18 pinnae; emergent leaves in whorls of 3–5, oblanceolate, mostly 5–6 mm long, glaucous, with 2–6 spreading lobes at base. Bracteoles linear, 0.8–1.6 mm long, entire or weakly toothed, cream; flowers solitary, sessile. Male flowers: sepals 4, orbicular, c. 0.1 mm long; petals 4, 1.4–1.5 mm long, yellow, red-tinted, caducous; stamens 8. Female flowers: sepals and petals absent; ovary 4-celled, styles clavate to conical, stigmas smooth, red. Fruit shortly cylindric, green-brown to reddish; mericarps cylindric, 1.8–2.1 mm long, with 3 longitudinal ridges, irregularly verrucose on dorsal surface. Flowers Sep.–Dec

LoM, MuF, MuM, NIS, VRiv, Wim. Rare and restricted to northern and north-western Victoria where it has been recorded growing in temporary waterholes, lagoons, farm dams and rock holes, and on clay pans.

This species is closely related to Myriophyllum caput-medusae, but is less robust, has a less branched inflorescence, all leaves whorled, smaller flowers, and larger fruits with different ornamentation (Orchard 1985).

Source: Jeanes, J.A. (1996). Haloragaceae. In: Walsh, N.G.; Entwisle, T.J. (eds), Flora of Victoria Vol. 3, Dicotyledons Winteraceae to Myrtaceae. Inkata Press, Melbourne.
Updated by: Val Stajsic, 2017-08-16

Orchard, A.E. (1985). Myriophyllum (Haloragaceae) in Australasia. II. The Australian Species, Brunonia 8: 173-291.

Hero image
Distribution map
life Life
kingdom Plantae
phylum Tracheophyta
superorder [Saxifraganae]
order Saxifragales
family Haloragaceae
genus Myriophyllum
Higher taxa


Source: AVH (2014). Australia's Virtual Herbarium, Council of Heads of Australasian Herbaria, <>. Find Myriophyllum porcatum in AVH ; Victorian Biodiversity Atlas, © The State of Victoria, Department of Environment and Primary Industries (published Dec. 2014) Find Myriophyllum porcatum in Victorian Biodiversity Atlas
  Bioregion Occurrence status Establishment means
Lowan Mallee present native
Murray Mallee present native
Wimmera present native
Victorian Riverina present native
Murray Fans present native
Northern Inland Slopes present native

State distribution

Distribution map