PROTECTING WISCONSIN'S BIODIVERSITY

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Scientific Name	Common Name	Global Rank	State Rank	Federal Status	WI Status

American Shoreweed (Littorella uniflora)

State Status: SC

Federal Status: none

State Rank: S2

Global Rank: G5

Photo by Robert H. Read

Counties with Mapped NHI Occurrences

American Shoreweed (Littorella uniflora), a Wisconsin Special Concern plant, is found in shallow to deep water of very soft, clear, oligotrophic lakes, usually with a sandy bottom. Blooming occurs throughout July, fruiting late-July through late-August. The optimal identification period for this species is late-July through August.

Synonyms:

Littorella americana, Littorella uniflora var. americana

Identification

American shoreweed is an emergent aquatic forb with an inflorescence that is unisexual, basal, and in groups of 3, sepals are 2.5-4mm long and lanceolate. Its fruits are cylindric achenes, 2mm long and half as wide. Its leaves are linear, terete, glabrous, and up to 5cm.

Distinguishing Characteristics and Similar Species

It can be distinguished from other small, linear-leaved aquatics simply by its round leaves, which only have one vein. Other small linear-leaved aquatic species have either bulbous leaf bases (Isoetes), triangular leaves (Eriocaulon), flat leaves (Juncus pelocarpus, Sagittaria and Valisneria) or stolons connecting clumps (Ranunculus flammula).

Phenology and Reproduction

Phenology

Blooming occurs throughout July, fruiting late-July through late-August.

Life Cycle, Optimum Time to Identify

Perennial. The optimal identification period for this species is late-July through late-August.

Ecology and Associated Species

Associated species include Lobelia dortmanna, Myriophyllum tenellum, Elatine minima, Isoetes species, Eriocaulon septangulare, and Gratiola aurea.

Habitat

American shoreweed is found in shallow to deep water of very soft, clear, oligotrophic lakes, usually with a sandy bottom.

Avoidance Measures and Management Guidance

Avoidance Measures

Avoid broadcast spraying of herbicides and use care with spot spraying.

Management Guidance

Minimize disturbance to hydrology, including soil disturbance from rutting.

This species is likely sensitive to water quality. Following BMPs around streams and buffering associated drainages will reduce eutrophication and prevent water quality degradation.

Wildlife Action Plan

Associated Natural Communities and Ecological Landscapes

Species of Greatest Conservation Need (SGCN) are associated with habitats (or natural communities) and places on the landscape. Understanding relationships among SGCN, natural communities and ecological landscapes help us make decisions about issues affecting SGCN and their habitat and how to respond. Download the Wildlife Action Plan association score spreadsheet to explore rare species, natural communities and ecological landscape associations

Issues/Threats and Conservation Actions

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the Wisconsin Wildlife Action Plan because lack of information can threaten our ability to successfully preserve and care for natural resources.

PROTECTING WISCONSIN'S BIODIVERSITY

American Shoreweed (Littorella uniflora)

Rare Species & Natural Communities

Additional Resources

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