Myriophyllum farwellii

Farwell's Milfoil

Farwell's Water Milfoil, Photo courtesy Wisconsin State Herbarium and Robert W. Freckmann
Farwell's Water Milfoil
Photo courtesy Wisconsin State Herbarium
and Robert W. Freckmann

Flora, fauna, earth, and sky...
The natural history of the northwoods


  • Myriophyllum, from the Greek, murios (myrios), "countless, infinite", and fullon (phyllon), "leaf; foliage"; hence "many leaved"
  • farwellii, from the Latin, "Farwell's", after American botanist Oliver Atkins Farwell (1867-1944)
  • Common name from the Latin, after O.A. Farwell
  • Other common names include: Farwell's Water Milfoil


  • Kingdom Plantae, the Plants
    • Division Magnoliophyta, the Angiosperms (flowering plants)
      • Class Magnoliopsida, the Dicotyledons
      • Subclass Rosidae
        • Order Haloragales
          • Family Haloragaceae, the Water Milfoils
            • Genus Myriophyllum, the Water Milfoils
  • Taxonomic Serial Number: 27043


  • A perennial aquatic herb, growing entirely under water
  • Leaves ¼"-1¼" long, dissected into threadlike segments, all or most leaves alternate, or more-or- less opposite, or irregularly scattered on stems.
  • Stem submerged, sparsely branched, freely rooting at lower nodes.
  • Turions present at end of stems.
  • Roots white, unbranched, and thread-like; growing from lower nodes. Not always present.
  • Flowers single, borne underwater in axils of leaves
    • Sepals inconspicuous
    • Petals 4, purple; on female flowers only
    • Stamens 4, tiny
    • Pistil 4-chambered
  • Fruit nut-like, 4-lobed with one seed per lobe; 2mm long, each fruit segment with 2 small, bumpy, longitudinal ridges.


  • A fully submerged aquatic plant, identifiable as a milfoil by its finely dissected, thread-like leaves.
  • Distinguished from other milfoils by
    • leaves alternate, rather than in whorls
    • a preference for small bodies of water


  • Nova Scotia and Quebec, to New York and Minnesota


  • Ponds and small lakes





  • Sexually by seed (uncommon)
  • Assexually by budding (most common)


  • Bydivision


  • Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
  • Useful as oxygenator in garden ponds, and as shelter for small fishes and aquatic invertebrates.



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Last updated on 26 February, 2004