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Dwarf Lake Iris (Iris lacustris)

Distribution & Habitat
Identification
Conservation
How You Can Help
Did You Know?

 
Distribution & Habitat

This miniature iris grows nowhere else in the world but in the Great Lakes Region. Most of the world's Dwarf Lake Iris population lies within Michigan's boundaries. It is known outside of Michigan only from Manitoulin Island and the Bruce Peninsula in Ontario, and the Door Peninsula of Wisconsin. It formerly grew near Milwaukee, Wisconsin. In Michigan, Dwarf Lake Iris is especially concentrated along certain stretches of the northern Great Lakes shoreline, where it may occur for miles, interrupted only by habitat destruction, degradation, or unsuitable habitat such as rocky points or marshy bays.

Map showing the distribution of Dwarf Lake Iris in Michigan

Dwarf Lake Iris usually occurs close to the Great Lakes shores on sand or in thin soil over limestone rich gravel or bedrock. It tolerates full sun to near complete shade, but flowers mostly in semi open habitats. These areas can be very long and narrow strips bordering the high water line, or large flat expanses located behind the open dunes of the Great Lakes shoreline. Many iris locations are on old beach ridges of former shores of the Great Lakes. Fluctuating water levels of the Great Lakes play a vital role in opening up new habitat for Dwarf Lake Iris. During high water years, trees and shrubs along the shoreline may be flooded out. This flooding may open up patches within the forest where the Dwarf Lake Iris may spread. It is usually found growing under White Cedar, although White Spruce, Balsam Fir, and Aspen are also frequently present. Other plants commonly growing with Dwarf Lake Iris include the lovely deep pink flowered Gay wings, white Starry False Solomon seal, and the brilliant orange red Indian Paintbrush.

 
Identification

Dwarf Lake Iris can be distinguished from other native iris species in Michigan by its very small size, and its thin, shallow, yellow rhizomes or underground stems. The slender rhizomes produce fans of flattened leaves that reach a height of about 6 inches. The leaves are light green and usually not more than 1/2 inch wide. Showy, deep blue flowers are produced singly on short stems, below the height of the leaves. It can grow in very large, dense, patches, forming a carpet of blue flowers from mid May to early June. A white flowered form is known from several locations in the Mackinac Straits Region and elsewhere. When the plant is not in flower, it can be confused with False Asphodel, a white flowered member of the lily family whose leaves are much narrower. The flower stalk of False Asphodel is much longer than that of iris and very sticky.

 
Conservation

Dwarf Lake Iris is found only on the northern Great Lakes shoreline of Lakes Michigan and Huron. It is threatened by loss of habitat due to increased human activity along the shoreline. Human disturbance such as shoreline development and intensive recreation are major threats. Dwarf Lake Iris is listed as a "threatened" species by the federal government and the state of Michigan. A permit is required for any project (including research, development, and construction) which may "take" or "harm" threatened or endangered species in Michigan.

In addition to aesthetic, ethical, and ecological reasons for protecting Earth's diverse species, another reason can be offered: selfinterest. The natural world is our life support system, providing countless medical, agricultural, and commercial benefits. For example, chemicals from plants are the sole or major ingredient in one quarter of all prescription medications in the United States. Scientists have shown that closely related plants usually have similar chemical components. The Yellow Flag, an iris native to Europe that has occasionally escaped from cultivation, has been used as a source of black dye and ink. If we choose to save wild species now, they may offer opportunities for us in the future. We do know that when a species becomes extinct, a unique set of genetic material whose use presently may be unknown, is lost forever.

To conserve the remaining populations of Dwarf Lake Iris, private, corporate, and public landowners and land managers who are likely to have Dwarf Lake Iris on their Great Lakes shoreline property are being contacted. Landowners have the opportunity to assist in the preservation of this remarkable component of Michigan's natural heritage. Other cooperative conservation efforts initiated by the Natural Heritage Program include:

  • protecting habitat within public natural areas and private nature preserves,
     
  • completing extensive surveys of known and potential habitat of endangered and threatened plants and animals, and
     
  • developing management plans with public agencies and private developers through state wide permitting and enforcement systems.

 
How You Can Help

  • Voluntarily protect coastal dunes and shoreline habitat where this and other special plants and animals of the Great Lakes live.
     
  • Learn the differences between Dwarf Lake Iris and False Asphodel.
     
  • Report your observations, including possible new locations of iris, by contacting the Michigan Department of Natural Resources.
     
  • Report destruction of this plant or the habitat in which it occurs by calling the Report All Poaching (R.A.P.) Hotline at 1 800 292 7800.
     
  • Become involved with a land conservation organization.
     
  • Support the Nongame Wildlife Fund by purchasing a wildlife habitat license plate, or through a direct contribution.

 
Did You Know?

This unique iris is Michigan's state wild flower.

"Lacustris" translates literally to mean "of lakes" and refers to where this beautiful iris grows. Dwarf Lake Iris was first found on Mackinac Island in 1810 by Thomas Nuttall, a renowned naturalist and explorer. Nuttall reached Mackinac Island after travelling from Detroit by canoe with French Canadian voyagers and the surveyor for the Michigan Territory. At least 1/3 of the species that Nuttall reported from the Great Lakes were new to science.

Acknowledgements: This information was written by Elaine A Chittenden with assistance from the Natural Heritage Program and Michigan Natural Features Inventory staff.