Northern Prairie Wildlife Research Center
Western Wetland Flora
Field Office Guide to Plant Species
Potamogeton filiformis Pers.
- Family: Pondweed (Potamogetonaceae)
- Flowering: July-September
- Field Marks: Only submersed leaves are present in this pondweed. The base of each leaf is attached to a stipule. This species differs from sago pondweed (P. pectinatus) by its less pointed leaves.
- Habitat: Quiet waters of ponds, lakes, and streams.
- Habit: Submersed perennial with much branched rhizomes, the tips of which sometimes
bear a small white tuber.
- Stems: Slender, branched.
- Leaves: All submersed, thread-like to linear, up to 1/6 inch wide but usually much
narrower, smooth, with 3-5 veins, with a stipule attached near its base.
- Flowers: Several in whorls of 2-8, the whorls crowded or separated on the stem, the stalk of the spike up to 6 inches long.
- Sepals: 4, brown, up to 1/8 inch long.
- Petals: O.
- Stamens: 4.
- Pistils: 4, each with a superior ovary.
- Fruits: Achenes obovoid, up to 1/6 inch long, up to 1/8 inch wide, with a short but
- Notes: This is an extremely variable species with regard to leaf width and degree of
congestion in the inflorescence. The achenes are eaten by waterfowl.
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