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Share your observations of plants or non-game animals with the Natural Heritage Inventory.
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- Contact information
- For information on Wisconsin's rare plants, contact:
- Kevin Doyle
608-416-3377
Lesser Duckweed (Lemna aequinoctialis)
Life history
Species overview
Lesser Duckweed (Lemna aequinoctialis), a plant, is found in quiet waters. Blooming occurs from spring through fall. The optimal identification period for this species is spring through fall.
Synonyms:
Identification
- Distinguishing characteristics: Root tips are usually sharp pointed. Most likely to be confused with Lemna perpusilla, which has several papules on the dorsal side of the leaves whereas Lemna aequinoctialis has only one.
- Flower characteristics: Tiny flowers without a perianth. Inflorescence consists of two male flowers and 1 female flower, enclosed in a spathe like a sac.
- Fruit characteristics: Utricle 0.5 to 0.8 mm long without wings. Seeds have 8 to 26 ribs.
- Leaf characteristics: Fronds are 1 to a few per plant, ovate to lanceolate and flat, 1 to 6 mm long and 1 to 3 times longer than wide, with entire margins and 3 veins. There is 1 papule near the apex on the dorsal side of the frond. No anthocyanins are present in this species of Lemna. The biggest air sacs are shorter than 0.3 mm.
Phenology
- Blooming phenology: spring through fall
- Fruiting phenology:
- Optimum time to identify: The optimal identification period for this species is spring through fall
Other
- Growth form: Aquatic
- Vegetative reproduction:
- Life cycle: Perennial
- Comments:
State status
Status and Natural Heritage Inventory documented occurrences in Wisconsin
Lesser Duckweed (Lemna aequinoctialis) is on the "watch list." Watch list species have experienced, or are believed to have experienced, a statewide or range wide decline, but they are not currently tracked in the Natural Heritage Inventory (NHI) database. The watch list includes newly discovered species for which origin and rarity need to be determined, certain animals designated as Species of Greatest Conservation Need (SGCN) in the Wisconsin Wildlife Action Plan, and species that were tracked in the past but proved more abundant, widespread or less vulnerable than previously thought. Although watch list species are not actively tracked by NHI, occurrences documented during surveys are often stored by NHI, as these species could be tracked in the future if there is further evidence of their decline.
| Summary Information | |
|---|---|
| State Status | none |
| Federal Status in Wisconsin | none |
| State Rank | SU |
| Global Rank | G5 |
| Tracked by NHI | W |
Habitats and landscapes
The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.
General habitat information
- Habitat description: Found in quiet waters.
- Soils:
Natural communities
This table lists the natural communities that are associated with Lesser Duckweed. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).
| Natural communities | score |
|---|
Ecological landscapes
This table lists the ecological landscape association scores for Lesser Duckweed. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.
| Ecological landscape | score |
|---|
Species guidance
The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.
Avoidance measures
These are specific actions designed to avoid "take" (mortality) of this species.
- No avoidance measures have been developed for this species.
Management guidance
Management guidelines are additional considerations that may help maintain or enhance habitat for this species
- No guidance has been developed for this species.
Other resources
Links to additional Lesser Duckweed information
Other links related to vascular plants (all exit the DNR website)
- Wisconsin Flora
- NatureServe Explorer
- Atlas of Wisconsin Prairie and Savanna Flora - Wisconsin State Herbarium
- USDA - NRCS Plants Database
- USGS Midwestern Wetland Flora - field office guide to plant species
- eFloras
- Cofrin Center for Biodiversity Herbarium
- Intermountain Herbarium Grasses of North America
- Orchids of Wisconsin
Photos
No additional photos are available for Lesser Duckweed at this time. Please consider donating a photo to the Natural Heritage Conservation Program.
Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin [exit DNR].
