The Diminutive and Prolific Common Duckweed

November 02, 2021


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Photographer: Patti Weeks

Summary Author: Patti Weeks 

The photo above at top shows tiny common duckweed plants floating on and around a decaying American lotus lily pad. They inhabit a shallow, still-water pond on the inland side of a boardwalk along the Pamlico River on the Washington, North Carolina waterfront. The bottom photo reveals a broader view of the extensive mat of duckweed, covering virtually the entire surface of the lily pond. Both photos were taken in September, 2021, at about the mid-life cycle of both plants.

The common duckweed (Lemna minor), along with other duckweed species, is the smallest known flowering plant, and is native throughout most of Africa, Asia, Europe and North America. The individual plant has 1–4 flat, oval leaves that are only 1/8 to 1/4 inch long (0.3 to 0.6 cm). Each plant has one single hanging root, and often contains a tiny hidden flower in a pouch-like sac. Its asexual reproduction is done by the intertwining of new stems from buds. Also, a turion can break from the parental stem and sink to the pond’s bottom to overwinter and resurface in the Spring to become a new bud.

By November, the duckweed and the lotus’s decayed lily pads and seeds will have sunk to the bottom of the pond, and the plants will re-emerge in the Spring to start their life cycles again. Because of its rapid growth, duckweed can often be a nuisance in homeowners’ ponds, but it’s an important food source for waterfowl and fish. It’s used for livestock feed and can also be used as a bioremediator of environmental and wastewater pollutants. In addition, research shows that duckweed has promising value in the creation of biomedicines.

Photo details: Top - SONY DSC-RX10 IV camera; 120.91 mm focal length; f/4; 1/1000 second exposure; ISO 100. Bottom - Same except 8.8 mm focal length.


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