European frog-bit
Hydrocharis morsus-ranae L.


Hydrocharis morsus-ranae is a free-floating aquatic plant that resembles a miniature water lily.
The leaves of the plant are round, and heart shaped, (the size of a Canadian two-dollar coin) with veins coming off the mid-vein that arch broadly following the shape of the leaf. The undersides of the leaves are dark purplish-red and have a spongy coating, which helps the plant float on top of the water.
It has a single white flower approximately 0.6 in. (1.5 cm) in diameter with three rounded petals and a yellow center.
Seeds are approximately 0.04 in. (1 mm) long.
Ecological Threat
In the fall, Hydrocharis morsus-ranae breaks apart and decomposes, falling to the bottom of the lake. The decomposition of huge volumes of vegetation in the water can deplete dissolved oxygen levels. If there are insufficient amounts of oxygen, fish and other aquatic organisms can die. These thick mats can also impede the movement of large fish and diving ducks.


Selected Images


EDDMapS Distribution

EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit

State Regulated List

State Regulated List - This map identifies those states that list this species on their regulated list. For more information, visit

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Liliopsida
Subclass: Alismatidae
Order: Hydrocharitales
Family: Hydrocharitaceae
Genus: Hydrocharis
Subject: Hydrocharis morsus-ranae L.


Plants - Aquatic Plants