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Plant Database

Search for native plants by scientific name, common name or family. If you are not sure what you are looking for, try the Combination Search or our Recommended Species lists.

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Wolffia arrhiza

Wolffia arrhiza (L.) Horkel ex Wimm.

Spotless Watermeal

Lemnaceae (Duckweed Family)

Synonym(s):

USDA Symbol: WOAR2

USDA Native Status: L48 (N)

 

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Plant Characteristics

Duration: Perennial
Habit: Herb
Size Notes: Floats on the surface of the water.
Fruit: Utricle.

Bloom Information

Bloom Color: Green
Bloom Time: May , Jun , Jul , Aug
Bloom Notes: Flowers are rare and inconspicuous, lacking sepals and petals. Plant also reproduces vegetatively.

Distribution

USA: CA
Native Distribution: Several sources say this species is naturalized in California. Calflora describes it as native.

Growing Conditions

Aquatic: yes

National Wetland Indicator Status

Region:AGCPAKAWCBEMPGPHIMWNCNEWMVE
Status: OBL
This information is derived from the U.S. Army Corps of Engineers National Wetland Plant List, Version 3.1 (Lichvar, R.W. 2013. The National Wetland Plant List: 2013 wetland ratings. Phytoneuron 2013-49: 1-241). Click here for map of regions.

Web Reference

Webref 30 - Calflora (2018) Calflora
Webref 38 - Flora of North America (2019) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
Webref 36 - Jepson eFlora (2019) The Jepson Herbarium, University of California, Berkeley

Additional resources

USDA: Find Wolffia arrhiza in USDA Plants
FNA: Find Wolffia arrhiza in the Flora of North America (if available)
Google: Search Google for Wolffia arrhiza

Metadata

Record Modified: 2023-04-10
Research By: TWC Staff

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