Lemna gibba
Duckweed
(c) Étienne Léveillé-Bourret, some rights reserved (CC BY) · licence
Family: Araceae · Type: Herb · Native
Lemna gibba (Duckweed) is a native California herb in the Araceae family, recognized by key diagnostic is the convex lower surface with enlarged air spaces.
Duckweed is a native perennial aquatic plant found in California's inland valleys, coastal regions, and central valleys in fresh or brackish water habitats at elevations generally below 1,500 meters. Flowering in summer, this tiny plant produces tiny green to yellow-green flowers often mottled with red. Growing in small clusters of two to three individuals, each plant is a tiny, glossy elliptical or round floating body typically 3 to 6 millimeters wide. Its leaf-like body has a symmetric base and asymmetric tip, with a slightly convex upper surface and enlarged air spaces that are often bordered in red. The fruit is distinctively winged, adding to the plant's delicate aquatic character.
Identification and appearance
Key characters: Co-occurs with 6 species; key diagnostic is the convex lower surface with enlarged air spaces
Habitat and range
Habitat: Common. Fresh or brackish water
Elevation: generally < 1500 m
California counties: San Bernardino, Riverside, San Mateo, Humboldt, Fresno, Santa Barbara, Sonoma, Yolo, San Diego, Ventura, Colusa, Monterey, Santa Clara, Mono, Merced, Sierra, San Luis Obispo, Santa Cruz, Inyo, Mendocino, Los Angeles, Orange, Kern, Siskiyou, Marin, Alameda, San Benito, Glenn, Lake, Nevada, Plumas, San Joaquin, Contra Costa, Butte, Imperial, San Francisco, Modoc, Sacramento
Outside California: worldwide
Bloom period
Lemna gibba blooms Summer.
How to tell it apart
vs Azolla: Lemna is smooth bright green with a single root; Azolla is feathery textured, often reddish, with no visible roots.; vs Callitriche: Lemna floats as separate tiny discs; Callitriche has distinct stems with opposite leaves forming small rosettes.; vs Nasturtium: Lemna is a tiny rootless-looking disc; Nasturtium has obvious stems, compound leaves, and grows rooted in mud.; vs Spirodela: Count the roots: Lemna has exactly one root per disc, Spirodela has multiple roots clustered together beneath each disc.; vs Landoltia: Count the roots: Lemna has one root per disc, Landoltia has 2-7 roots hanging down like a tiny broom.
Frequently asked questions
Is Lemna gibba native to California?
Yes. Lemna gibba is native to California (recorded as native).
When does Lemna gibba bloom?
Lemna gibba blooms Summer.
Where in California does Lemna gibba grow?
Lemna gibba occurs in San Bernardino, Riverside, San Mateo, Humboldt, Fresno, Santa Barbara, Sonoma, Yolo and other counties, at elevations of generally < 1500 m.
What plant family does Lemna gibba belong to?
Lemna gibba is in the Araceae family, genus Lemna.
What habitat does Lemna gibba grow in?
Lemna gibba grows in Common. Fresh or brackish water.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.