Spirodela polyrhiza
Giant duckweed

Giant duckweed is a native floating plant in Florida. Though very small, it is the largest of the duckweeds. This plant can grow into dense masses in stagnant water bodies.

Giant duckweed has two to three rounded leaves, which are usually connected. Giant duckweeds usually have several roots (up to nine) hanging beneath each leaf. The underleaf surface of giant duckweed is dark red.


This plant is easily confused with the exotic plant, Landoltia punctata. Landoltia duckweed is smaller than Spirodela polyrhiza, is more shoe-shaped, does not have a red dot on top, usually has only up to 4 roots, and sometimes has a red margin on the underneath of the leaves. The native, Spirodela polyrhiza, giant duckweed, is larger, has rounder leaves, some have a red dot on the top, has up to 9 and more roots, and is dark red underneath the leaves.


See how Spirodela polyrhiza compares with the other duckweeds on the duckweeds comparison page.