European water-clover

Scientific Name: Marsilea quadrifolia

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Identification: European water clover is an aquatic fern that grows from creeping horizontal stems anchored in the muddy bottoms of shallow ponds and lakes. Its name refers to its four-part leaves that resemble a clover. This species’ smooth leaves distinguish it from other water clover species, which have fuzzy leaves. Leaves float on or just below the surface in deep water, but they stand above the surface in shallow water. European water clover is also known as water shamrock, pepperwort, and four-leaf clover.

Size: European water clover grows to a maximum height of 8 inches (20 cm).

Native Range: This species is native to Eurasia.

Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Marsilea quadrifolia are found here.

Full list of USGS occurrences

State/ProvinceYear of earliest observationYear of last observationTotal HUCs with observations†HUCs with observations†
Michigan196120183Clinton; Great Lakes Region; Huron
New York189320145Great Lakes Region; Niagara; Oak Orchard-Twelvemile; Seneca; St. Lawrence

Table last updated 9/30/2019

† Populations may not be currently present.

* HUCs are not listed for areas where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).

Means of Introduction: This fern is often found in artificial bodies of water. This may indicate it was intentionally planted and has since escaped cultivation.

Status: European water clover has been well established for more than 100 years in much of the northeastern United States and as far west as Iowa and Missouri. The first Great Lakes sighting was in 1925 in the Lake Ontario drainage.

Remarks: In some cultures, this plant is used for food and medicine.

Author: Illinois-Indiana Sea Grant

Contributing Agencies:
NOAA Sea Grant GLRI Logo

Revision Date: 9/25/2012

Citation for this information:
Illinois-Indiana Sea Grant, 2019, European water-clover: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI,, Revision Date: 9/25/2012, Access Date: 12/11/2019

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.