Water lettuce (Pistia stratiotes)

Common Names: Tropical duckweed

Description: Best surveyed in summer and fall, can be identified throughout the growing season.

Habit: Free floating aquatic plant; forms a rosette; feathery roots extend up to 80cm (32 in) below water surface.

Leaves: Thick and ridged, dull light green in color, short velvety hairs.

Stems: Stemless.

Flowers: Inconspicuous flowers on stalk in center of rosette; cluster of male flowers about and single female flower below.

Fruit and seeds: Fruit is a green berry.

Habitat: Found in ponds, lakes, ditches, slow-moving or still water.

Reproduction: Vegetatively or by seed; daughter plants form on stolons. Typically introduced via water gardens; may also be spread by boats and trailers.

Monitoring and rapid response: Hand-pulling for small infestations; mechanical chopping/harvesting.

Credits: The information provided in this factsheet was gathered from the Michigan Natural Features Inventory and the Wisconsin Department of Natural Resources.

Individual species images that appear with a number in a black box are courtesy of the Bugwood.org network (https://www.invasive.org).Individual photo author credits may not be included due to the small display size of the images and subsequent difficulty of reading the provided text. All other images appear courtesy of Google (https://images.google.com).

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