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Seaside Spurge (Euphorbia polygonifolia)

Life history

Species overview

Seaside Spurge (Euphorbia polygonifolia), a Wisconsin Special Concern plant, is found on sandy beaches and dunes along Lake Michigan. Blooming occurs early July through late August; fruiting occurs early August through early October. The optimal identification period for this species is early July through late September.

Synonyms: Chamaesyce polygonifolia


  • Distinguishing characteristics: Unlike other members of this genus, the petal-like appendages of the cyathium are absent or barely visible on E. polygonifolia.
  • Flower characteristics: Staminate and pistillate flowers arranged in a "false flower" called a cyathium located near pairs of leaves; staminate flowers located around and below the pistillate flower, which is in the center of the cyanthium.
  • Fruit characteristics: Seeds plump, smooth, compressed-ovoid, gray, 2 to 2.6 mm, widely distributed.
  • Leaf characteristics: Opposite, linear-oblong to lance-oblong, mostly 8 to 15 mm, entire, slightly inequilateral at base. Appendages very small or none.


  • Blooming phenology: early July through late August
  • Fruiting phenology: early August through early October
  • Optimum time to identify: The optimal identification period for this species is early July through late September


  • Growth form: Forb-prostrate
  • Vegetative reproduction:
  • Life cycle: Annual
  • Comments: Associated Species: Cakile edentula, Corispermum hyssopifolium, Elymus lanceolatus ssp. psammophilus, Ammophila breviligulata, Juncus balticus, Prunus pumila, Artemisia cuadata.

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 Seaside Spurge (Euphorbia polygonifolia). 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 Euphorbia polygonifolia in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS2
Global RankG5?
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 on sandy beaches and dunes along Lake Michigan.
  • Soils: Sandy soils.

Natural communities

This table lists the natural communities that are associated with Seaside Spurge. 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
Great Lakes Beach 3
Great Lakes Dune 3

Ecological landscapes

This table lists the ecological landscape association scores for Seaside Spurge. 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.

  • Avoid broadcast spraying of herbicides; use care with spot spraying.
  • Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.

Management guidance

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

  • Avoid any activities which destabilize the dune, including the use of off-road vehicles, removal of native vegetation and pedestrian recreational overuse.
  • Avoid disturbance to shorelines and the forest-beach interface.


Seaside Spurge Photo.

Photo by Kevin Doyle, Wisconsin DNR.

Seaside Spurge Photo.

Photo © Emmet Judziewicz.

Seaside Spurge Photo.

Photo © Emmet Judziewicz.

Seaside Spurge Photo.

Photo © Eric Howe.

Seaside Spurge Photo.

Photo by Kevin Doyle, Wisconsin DNR.

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, May 05, 2021
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