Plants and Animals

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

US Status:
State Status: T - Threatened (legally protected)
Global Rank: G5 - Secure
State Rank: SNR - Not ranked

Occurrences

CountyNumber of OccurrencesYear Last Observed
Baraga12008

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

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

  • Headwater stream (1st-2nd order), riffle
  • Headwater stream (1st-2nd order), pool
  • Headwater stream (1st-2nd order), run
  • Submergent marsh

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

Management Recommendations

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. 

Survey Methods

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

  • Meander search

    • Survey Period: From first week of June to first week of September

      Survey Method Comment:
      Survey would be optimal during flowering/fruiting period, but plants can be recognized in sterile/vegetative condition.

References

Survey References

  • Elzinga, C.L., D.W. Salzer, and J.W. Willoughby. 1998. Measuring and Monitoring Plant Populations. The Nature Conservancy and Bureau of Land Management, Denver. BLM Technical Reference 1730-1. 477pp.
  • Nelson, J.R. 1984. Rare Plant Field Survey Guidelines. In: J.P. Smith and R. York. Inventory of rare and endangered vascular plants of California. 3rd Ed. California Native Plant Society, Berkeley. 174pp.
  • Nelson, J.R. 1986. Rare Plant Surveys: Techniques For Impact Assessment. Natural Areas Journal 5(3):18-30.

Technical References

  • Crow, G.E. and C.B. Hellquist. 2000. Aquatic and Wetland Plants of Northeastern North America. Volume 1. Pteridophytes, Gymnosperms, and Angiosperms: Dicotyledons. University of Wisconsin Press, Madison. 480pp.
  • Fernald, M.L. 1950. Gray's Manual of Botany; eighth edition, illustrated. D. Van Nostrand Company. lxiv + 1632 pp.
  • Flora of North America Editorial Committee. 2010. Flora of North America, North of Mexico. Volume 7: Magnoliophyta: Salicaceae to Brassicaceae. Oxford Univ. Press. New York, NY. 797 pp.
  • Gleason, H. A., and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Second edition. The New York Botanical Garden, Bronx. 910pp.
  • Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the vascular plants of Northeastern United States and adjacent Canada. New York Botanical Garden, Bronx. 937pp.
  • Scoggan, H.J. 1978. The Flora of Canada. National Museum of Natural Science Publications Botany 4: 1711pp.