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Northern Slender Pondweed (Stuckenia filiformis ssp. alpina)

Life history

Species overview

Northern Slender Pondweed (Stuckenia filiformis ssp. alpina), a Wisconsin Special Concern plant, is found in marshes and swamps with calcareous to brackish water. Blooming occurs from May through July. The optimal identification period for this species is spring to early fall.

Synonyms: Coleogeton filiformis ssp. alpinus, Potamogeton filiformis var. alpinus, Potamogeton filiformis var. borealis, Potamogeton filiformis var. macounii, Stuckenia filiformis var. alpina


  • Distinguishing characteristics: Of other Stuckenia species found in Wisconsin, Stuckenia vaginata has midstem stipular sheaths that are disticntly inflated; Stuckenia pectinata has acute leaf apexes; and Stuckenia filiformis ssp. occidentalis has loosely clasping stipules that disintegrate with age.
  • Flower characteristics: Four-parted, small flowers in a single, small spike.
  • Fruit characteristics: Fleshy fruit 2.2 to 3 mm long.
  • Leaf characteristics: Alternate leaves have a prominent midvein, are very narrow and 0.2 to 1 mm wide with tightly clasping stipular sheaths and blunt, notched apexes.


  • Blooming phenology: May through July
  • Fruiting phenology:
  • Optimum time to identify: The optimal identification period for this species is spring to early fall


  • Growth form: Aquatic herb
  • Vegetative reproduction: Rhizomatous
  • Life cycle: Perennial
  • Comments:

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Northern Slender Pondweed (Stuckenia filiformis ssp. alpina). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Documented locations of Stuckenia filiformis ssp. alpina in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS2
Global RankG5T5
Tracked by NHIY

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

  • Habitat description: Found in marshes and swamps with calcareous to brackish water.
  • Soils:

Natural communities

This table lists the natural communities that are associated with Northern Slender Pondweed. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Natural communities score
Submergent Marsh 3

Ecological landscapes

This table lists the ecological landscape association scores for Northern Slender Pondweed. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Map of the Ecological Landscapes of Wisconsin.

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

  • No avoidance measures have been developed for this species.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

  • No guidance has been developed for this species.


Northern Slender Pondweed Photo.

Scanned specimen courtesy of Wisconsin Herbarium

Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin [exit DNR].

Last revised: Wednesday, October 14, 2020
Southwest Savanna Southern Lake Michigan Coastal Western Coulees and Ridges Southeast Glacial Plains Central Sand Hills Central Lake Michigan Coastal Central Sand Plains Northern Lake Michigan Coastal Northern Lake Michigan Coastal Northeast Sands Western Prairie North Central Forest Northern Highlands Northwest Lowlands Northwest Sands Northwest Lowlands Superior Coastal Plains Forest Transition