Aquatic or semi-aquatic herb with roots formed on the lower nodes. Submerged leaves in whorls, emergent ones in whorls of 5-6, deeply pinnately divided into 24-36 segments, waxy-blue. Sexes on separate plants but male plants are not present in Australia. Flowers solitary in the leaf axils. Female flowers 4-parted. Fruit not formed in Australia.
A potential major weed of waterways and already naturalised in shallow water bodies, pools and creeks in Qld, NSW,Vic and Tas. Grows prolifically where nutrient levels are high, forming dense rafts of vegetation in slow-flowing water from which stems are easily torn to become new plants.
Other species are occasionally offered but the large, feather-like, whorled, waxyblue leaves are very distinctive for this species.
C South America.
Source: (2002). Haloragaceae. In: . Horticultural Flora of South-eastern Australia. Volume 3. Flowering plants. Dicotyledons. Part 2. The identification of garden and cultivated plants. University of New South Wales Press.