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Invasive Species Sheet - Non-Native Water-milfoils

Invasive Species Identification Sheet

Non-Native Water-milfoils (Myriophyllum L.)

  • herbaceous water plants (2 very invasive Water-milfoils are included on this card)
  • underwater leaves in whorls; feathery, with many pairs of threadlike divisions
  • there are many non-native and native species of Water-milfoil; ASK EXPERTS FOR HELP
  • be suspicious of thick, dense growths of underwater stems with whorled feathery leaves

Parrotfeather Myriophyllum aquaticum (Vell.) Verdc.
Alternate Common Names: Parrotfeather Milfoil; Brazilian Parrot’s Feather
Alternate Latin Names: Enydria aquatica Vell.; Myriophyllum brasiliense Camb.; Myriophyllum proserpinacoides Gillies ex Hook. & Arn.

  • leaves above water’s surface resemble little conifer trees with bright green leaves, ¾"-2"
  • leaves are mostly above water, each with 6-18 paired divisions;
  • underwater leaves, when present, have 20-30 paired divisions
  • plant never produces turions (bulb-like shoots from the base or other parts of the stem)

Eurasian Water-Milfoil Myriophyllum spicatum L.
Alternate Common Name: Spike Watermilfoil

  • underwater leaves usually in whorls of 4 (3-5) individual leaves; each less than 1½" long
  • underwater leaves most often with (9-)12-24 tightly-spaced, paired divisions
  • underwater leaves tend to collapse around stem when pulled out of water
  • stem frequently tan or tan-red; whorls widely spaced compared to leaf length
  • leaf outline is usually narrower than an egg’s shape; leaves look clipped (squared) at tips
  • plant never produces turions (bulb-like shoots from base or other parts of the stem)
  • small leaves above the water’s surface are undivided and not toothed; flowers are pinkish