Wolffia borealis
Northern water meal
(c) Ethan Rose, some rights reserved (CC BY) · licence
Family: Araceae · Type: Herb · Native
Wolffia borealis (Northern water meal) is a native California herb in the Araceae family, recognized by acute upturned tip and brown coloration when dead.
Northern water meal is a native perennial found in northern coastal California, high Cascade Range, and southern California coastal regions in freshwater habitats at elevations below 1,000 meters. Flowering during summer to early fall, this tiny plant produces subtle green flowers less than 1.2 millimeters long. Growing as an extraordinarily small floating aquatic plant, it forms delicate green colonies on water surfaces. Its body is dark green and transparent underneath, with a slightly concave upper surface and an acute, upturned tip. This diminutive plant contains between 50 to 100 stomates, making it a remarkable example of miniature botanical complexity.
Identification and appearance
Key characters: 3 sympatric species; distinguished by acute upturned tip and brown coloration when dead
Habitat and range
Habitat: Uncommon. Freshwater
Elevation: < 1000 m
Outside California: to northern United States, Canada
Bloom period
Wolffia borealis blooms Summer-early fall.
How to tell it apart
vs Lemna: Wolffia is spherical and 0.4-1.3 mm; Lemna is disc-shaped, larger, and has a root.; vs Landoltia: Wolffia is spherical, rootless, and 0.4-1.3 mm; Landoltia has 2-7 roots and is much larger.; vs Spirodela: Wolffia is spherical, rootless, and 0.4-1.3 mm; Spirodela has 7-16 roots and is much larger.; vs Wolffiella: Wolffia is spherical like caviar; Wolffiella is flat and ribbon-shaped.
Frequently asked questions
Is Wolffia borealis native to California?
Yes. Wolffia borealis is native to California (recorded as native).
When does Wolffia borealis bloom?
Wolffia borealis blooms Summer-early fall.
What plant family does Wolffia borealis belong to?
Wolffia borealis is in the Araceae family, genus Wolffia.
What habitat does Wolffia borealis grow in?
Wolffia borealis grows in Uncommon. Freshwater.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · 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.