Wolffia borealis — northern water-meal
![Thalli: Wolffia borealis. ~ By Gordon Morrison. ~ Copyright © 2024 New England Wild Flower Society. ~ Image Request, images[at]newenglandwild.org](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Araceae/wolffia-borealis-ta-gmorrison.jpg)
![Plant form: Wolffia borealis. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Araceae/wolffia-borealis-ha-ahaines.jpg)
![Plant form: Wolffia borealis. ~ By Andrew Nelson. ~ Copyright © 2024 Andrew Nelson. ~ andrew.nelson[at]oswego.edu ~ Flora of Rice Creek Field Station - www.oswego.edu/academics/opportunities/rice_creek_field_station](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Araceae/wolffia-borealis-ha-anelson2.jpg)
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Facts
Northern water-meal is absent from much of northern New England, except in Vermont's Champlain Valley. Water-meal (Wolffia) species have no roots. In a study comparing northern water-meal with common duckweed (Lemna minor) and common duck-meal (Spirodela polyrrhiza), northern water-meal had the fastest rate of production (0.62 fronds per day).
Habitat
Lacustrine (in lakes or ponds), riverine (in rivers or streams)
New England distribution
Adapted from BONAP data
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
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enlargeCharacteristics
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Vermont
- Roots
- there are no roots on the plant
- Thallus shape in cross-section
- the thallus is somewhat flattened on at least one side in cross-section
- Thallus length
- 0.7–1.5 mm
- Thallus shape
- the thallus is another shape in outline
- Thallus dimensions
- 1.3–2
- Veins on upper surface
- 0
-
Flowers
- Scale surrounding flower
- no
- Stamen number
- 1
-
Fruits or seeds
- Seed surface ribbed
- the seed surface is nearly smooth
-
Growth form
- Root length
- 0 mm
- Root number
- 0
- Root sheath winged at base
- NA
- Roots
- there are no roots on the plant
- Roots perforating basal scale
- NA
- Thallus dimensions
- 1.3–2
- Thallus edge
- the edge of the thallus is smooth (without teeth) near the tip
- Thallus length
- 0.7–1.5 mm
- Thallus shape
- the thallus is another shape in outline
- Thallus shape in cross-section
- the thallus is somewhat flattened on at least one side in cross-section
- Thallus stalks
- the thallus does not have a stalk
- Thallus width
- 0.4–1.2 mm
- Thallus with red pigment
- no
- Turions
- yes
-
Leaves
- Papilla on thallus
- no
- Veins on upper surface
- 0
-
Place
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Vermont
- Specific habitat
-
- in lakes or ponds
- in rivers or streams
Wetland status
Occurs only in wetlands. (Wetland indicator code: OBL)
In New England
Distribution
- Connecticut
- absent
- Maine
- present
- Massachusetts
- present
- New Hampshire
- present
- Rhode Island
- absent
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- unranked (S-rank: SNR), #NAME? (code: #NAME?)
From Flora Novae Angliae dichotomous key
1. Wolffia borealis (Engelm. ex Hegelm.) Landolt ex Landolt & Wildi N
northern water-meal. Wolffia brasiliensis Weddell var. borealis Engelm. ex Hegelm.; W. punctata, auct. non Griseb. • CT, MA, ME, NH, VT; extending north in the Lake Champlain Valley but absent over much of northern New England. Mesotrophic to eutrophic waters of lakes, rivers, and backwaters.