Caltha natans
Floating marsh marigold

Key Characteristics

Small aquatic plant of shallow, slow-moving streams, beaver ponds, and stream mouths; with floating to creeping stems that root at the nodes, bearing 2-5 cm wide, heart-shaped leaves with coarsely scalloped margins, and producing small, 1 cm wide, white to occasionally pink-petaled flowers.

Status and Rank

  • State Status: T
  • State Rank: SNR
  • Global Rank: G5


County NameNumber of OccurrencesYear Last Observed
Distribution map for Caltha natans

Updated 5/15/2018. 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.


Usually occurs in ponds and shallow, slow-flowing streams, especially those influenced by beaver activities, with colonies sometimes ranging into the shallow water zones of lakes near stream mouths.  Plants root in muddy/mucky substrates and may be found stranded on exposed mud flats, whereas elsewhere this species has also been observed in artificial habitats such as drainage ditches.

Natural Community Types


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-starwort, pondweed


Little is known about the ecology of this recently discovered species in Michigan, but it is likely that the conservation of hydrological regime, including annual cycles of flooding and water table fluctuations, is necessary to perpetuate populations.

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 [Accessed Aug 18, 2018]


Survey References

Technical References

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