Rorippa aquatica
Lake cress
Image of Rorippa aquatica

Photo by Donald H. Les 

Key Characteristics

Emergent aquatic plant of lake margins and slowly moving streams; underwater leaves alternate, twice-pinnate on a central axis, falling off when lifted from water.

Status and Rank

  • State Status: SC
  • State Rank: S2
  • Global Rank: G4?

Occurrences

County NameNumber of OccurrencesYear Last Observed
Alpena31984
Cheboygan61984
Gratiot11889
Ionia11889
Iosco11937
Luce11971
Mackinac11975
Macomb21900
Marquette11976
Mason11932
Muskegon11898
Presque Isle41981
Distribution map for Rorippa aquatica

Updated 1/31/2017. Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.

Habitat

An aquatic plant, this species is found in quiet, shallow water along lake margins and back water areas of slowly moving streams. It roots in organic or sandy substrates.

Natural Community Types

Methodology

For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Associated Plants

Water-plantain, sedges, spike-rush, northern manna grass, cut grass, smartweed, arrowhead, bur-reed, cat tails, wild rice, water-milfoil, watercress, and great duckweed.

Management

This species requires high water quality and natural hydrology.

General Survey Guidelines

Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgment of the investigator.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed Jun 27, 2017]

More Information

See MNFI Species Abstract

References

Survey References

Technical References

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