Botrychium minganense Victorin
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Botrychium lunaria var. minganense
Basis for Listing
Botrychium minganense is a widespread moonwort, occurring in North America at northern latitudes and at higher elevations in the south. It occurs from Newfoundland and New England westward across the northern U.S. and Canada to Alaska, and in the western mountains. One occurrence has also been reported from outside North America in Iceland (Farrar 2006).
Botrychium minganense is a small, perennial fern 8-25 cm (3.1-9.8 in.) in height. It is divided above ground into the spore bearing portion (sporophore) and the sterile blade (trophophore). The trophophore is yellowish-green, clearly stalked, and has up to 10 pairs of pinnae. Pinnae are often fan shaped with entire to shallowly lobed margins, and of similar size and spacing along the rachis. The sporophore is typically equal to or longer than the trophophore at the time of spore release.
In Minnesota, B. minganense has most frequently been found in mesic hardwood forests. It has also been observed in upland cedar forest, aspen-fir forest, wet cliff (mossy ledge of waterfalls), and old openings and trails. Associated plant species may include other species of Botrychium (moonworts & grapeferns), Acer saccharum (sugar maple), Tilia americana (basswood), Uvularia grandiflora (large-flowered bellwort), and Aralia nudicaulis (wild sarsaparilla).
Biology / Life History
The sexual life cycle of Botrychiums is characterized by an alternation of generations between sporophytes and gametophytes. Botrychiums reproduce by spores shed from the thick walled sporangia of the sporophore. Spores find their way down into the soil and further develop into subterranean gametophytes. Gametophytes contain no chlorophyll and develop mycorrhizal relationships for nourishment. They typically exist underground for a number of years before producing eggs and sperm. Self-fertilization often occurs, where eggs are fertilized from the sperm of the same plant. The fertilized egg further develops as the new sporophyte, taking several years to surface above ground and produce its first frond and spores. Plants are perennial, and may not produce above ground parts every year. Botrychium minganense is also capable of asexual reproduction by the production of tiny gemmae at the root bases (D. Farrar, Iowa State University, pers. comm.). These gemmae have the ability to grow into new plants.
Conservation / Management
Although we continue to gain a better understanding of species distribution and abundance, we often know little more. The most obvious threats to Botrychium minganense are the loss and degradation of habitat. However, finer details regarding specific habitat requirements are much less certain. More specific threats likely include changes in light, moisture and mycorrhizae; earthworm invasion; insectivory and herbivory; and competition from non-native species. Well-designed monitoring efforts are necessary in order to better understand species ecology and how populations are responding to management activities and a changing environment. Ample opportunities currently exist across land ownerships to learn more about the biology and ecology of this interesting small fern.
Conservation Efforts in Minnesota
Botrychium minganense populations occur on tribal, state, federal, and other land ownerships. While many of the populations occur on state and federal land, few if any occur in areas that are formally protected. In 2009, survey work will continue in portions of the Chippewa Plains, Nashwauk Uplands, and Border Lakes subsections, all of which have potential for new discoveries of B. minganense.
Chadde, S., and G. Kudray. 2001. Conservation Assessment for Botrychium minganense (Mingan Moonwort). United States Forest Service, Eastern Region, Milwaukee, Wisconsin.
Farrar, D. R. 2006. Moonwort (Botrychium) Systematics.
Minnesota Department of Natural Resources. 2003. Field guide to the native plant communities of Minnesota: the Laurentian mixed forest province. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul, Minnesota. 352 pp.
Wagner, W. H., Jr., and F. S. Wagner. 1993. Botrychium. Pages 86-101 in Flora of North America Editorial Committee, editors. Flora of North America north of Mexico. Volume 2. Oxford University Press, New York.