Plants of South Eastern New South Wales
Myriophyllum pedunculatum
Common name
Water-milfoil
Family
Haloragaceae
Where found
Swampy ground, margins of lakes, pools, and Sphagnum bogs, and in shallow water. Widespread but not coastal.
Notes
Perennial herb, rooting at the nodes, prostrate, mat forming or sprawling, to 0.25 m tall. Leaves opposite each other, 0.2–2.2 cm long, linear to cylindrical or threadlike, with a terminal gland, margins entire or with 1 or 2 lobes. The plants become reddish as the mud dries out. Male and female flowers on the same shoot, or on different shoots on the same plant, or male and female flowers on different plants. Male flowers with 4 hooded red to yellow petals 1.5–2.5 mm long. Female flowers with 0 sepals, 0 petals, stigmas feathery, usually red. Flowers single at the base of opposite leaves.
Definite identification of species of Myriophyllum often requires microscopic examination of the seeds, beyond the scope of this key.
subsp. longibracteolatum: Stems weak, more or less erect. Leaves widely spaced, thread-like, 1.5–2.2 cm long, 0.5-1 mm wide, often with 1 or 2 slender lobes near the middle.
subsp. pedunculatum: Main stems prostrate, robust, slighty fleshy, tips pointing up, to 0.1 m tall. Leaves closely spaced, linear to cylindrical, 0.4–1.1 cm long, somewhat fleshy, entire.
Nearly all records are from subsp. pedunculatum.
All native plants on unleased land in the ACT are protected.
PlantNET description of species and key to subspecies: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Myriophyllum~pedunculatum (accessed 24 January, 2021)
This identification key and fact sheets are available as a free mobile application:
