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Eurasian watermilfoil (Myriophyllum spicatum)

Description

Myriophyllum spicatum (Eurasian watermilfoil or spiked water-milfoil) is native to Europe, Asia, and north Africa. It is a submerged aquatic plant, and grows in still or slow-moving water. Eurasian watermilfoil has slender stems up to 175 cm long. The submerged leaves (usually between 15–35 mm long) are borne in pinnate whorls of four, with numerous thread-like leaflets roughly 4–13 mm long. Plants are monoecious with flowers produced in the leaf axils (male above, female below) on a spike 5–15 cm long held vertically above the water surface, each flower inconspicuous, orange-red, 4–6 mm long. Eurasian water milfoil has 12- 21 pairs of leaflets while northern watermilfoil M. sibiricum only has 5–9 pairs. The two can hybridize and the resulting hybrid plants can cause taxonomic confusion as leaf characters are intermediate and can overlap with parent species. Myriophyllum spicatum is now found on all continents except Australia, where there have been only anecdotal sightings, and Antarctica.

Taxonomic tree

  • Domain: Eukarya

    • Kingdom: Plantae

      • Phylum:

        • Class: Magnoliopsida

          • Order: Saxifragales

            • Family: Haloragaceae

              • Genus: Myriophyllum