Mistflower (Argeratina riparia)
Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Eudicots
(Unranked): Asterids
Order: Asterales
Family: Asteraceae
Genus: Ageratina
Species: A. riparia
Binomial name: Ageratina riparia
Common name: Mistflower
Mistflower a native of Mexico and is an erect or sprawling perennial herb that grows up to 40x60 cm high. Numerous, reddish-brown stems may become semi-woody, & root at joints where they touch the ground.
Dark green, opposite leaves are toothed, taper at ends & have prominent veins. The serrated leaves on average reach 7.5 cm long and 2.5 cm wide.
Clusters of small white flowers form dense heads at the ends of the branches. (Aug-Dec, sometimes to Mar).
Plant may produce 100,000 small, dark brown seeds per year. These seeds are black, slender, angular, 2 mm long, with fine white hairs at the tip.
Seeds mostly dispersed by wind & also by water, gravel, & in mud sticking to clothing, machinery, animals etc. Existing plants spread vegetatively by layering of trailing branches.
It grows in a wide range of habitats, preferring warm, wet, semi-shaded areas. It tolerates shade, & wet & dry conditions.
Its impact on environment is that it smothers native plant communities. Its a major weed of stream banks, causing sediment build up, flooding & instability of steep gullies & streams.
Two agents have been released to attack the mistflower. The Mistflower fungi (Entyloma ageratinae) and the mistflower gall fly (Procecidiocharis alani). These two agents have been successful in controlling the Mistflower in Hawaii. Both have established well and have stopped the plant from spreading and have reduced its abundance to much lower levels.
Mistflower was once harvested to use as a tanning agent.
Upper surface of the leaf
Underneath surface of a leaf
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