Eurasian water milfoil

Myriophyllum spicatum
Class 1 noxious weed throughout NSW under the NSW Noxious Weeds Act 1993 its dense canopy can interfere with boating, swimming, fishing, or other aquatic activities. Suppresses native plants; impacts equilibrium between aquatic organisms
Family: Haloragaceae
Origin: Eurasia
Habit: Submerged perennial aquatic herb in water from 0.5 to 10 m deep, reddish-brown to whitish-pink stems from root crown branch repeatedly into a dense leaf canopy very close to the surface
Leaves: Feather like, pinnately compound ,olive-green, less than 4 cm long, in groups of four whorled at each node of the stem, usually with more than 12 divisions
Flowers: Pink small four petalled flowers in whorls held on spike up to 8 cm above water lie parallel when wind pollinated fruit sets
Fruit and Seeds: Wind pollinated fruit minor in forming new colonies
Roots: Crown with branching stems
Dispersal: Reproduction is almost entirely vegetative
Control: Shading, manual harvesting, mechanical harvesting can cause reinfestation with fragmentation, manipulation of water levels useful
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