Mingan Moonwort

Botrychium minganense Victorin

Carex amphibola var. amphibola
Troy Weldy

Ophioglossaceae (adder's-tongue family)
State Protection
Listed as Endangered by New York State: in imminent danger of extirpation in New York. For animals, taking, importation, transportation, or possession is prohibited, except under license or permit. For plants, removal or damage without the consent of the landowner is prohibited.
Federal Protection
Not Listed
State Conservation Status Rank
Critically Imperiled in New York - Especially vulnerable to disappearing from New York due to extreme rarity or other factors; typically 5 or fewer populations or locations in New York, very few individuals, very restricted range, very few remaining acres (or miles of stream), and/or very steep declines.
Global Conservation Status Rank
Secure globally - Common in the world; widespread and abundant (but may be rare in some parts of its range).


Did you know?

The underground gametophyte (the separate plant that germinates from the spore and produces the egg and sperm cells) does not produce chlorophyll and is dependent on a fungus for its nutrition. Plants may live underground for more than one year and all of the plants in one population may not be seen every year. This fern was recognized as a separate species in 1927 and was named for Mingan Island in the northern Gulf of St. Lawrence.

State Ranking Justification

There is only one known location for this fern in the state. No other historical populations were recorded.

Short-term Trends

The only existing population has seen a reduction in numbers but the severity is complicated by the difficulty in counting individuals without harming them and the added difficulty of distinguishing them from the closely related Botrychium lunaria. All the plants may not appear each year so long-term counts must be done to verify trends.

Long-term Trends

Only one location was ever known for this fern in the state.

Conservation and Management


The primary threat to Botrychium minganense is the loss of its open habitats to successional overgrowth and development. Trampling by visitors to the only known site is also a threat since the plants are small and easily overlooked.

Conservation Strategies and Management Practices

An evaluation of the management needs of the existing population should be undertaken.

Research Needs

A long-term demographic study should be undertaken to understand the biology and trends of this plant in New York.



This is a fern of northern white cedar forests and open pastures that are casually grazed where the underlying bedrock is calcareous. Often found with other moonworts (New York Natural Heritage Program 2005). Open fields and meadows, or sandy or gravelly streambanks (Gleason and Cronquist 1991). In dry pastures, meadows, and on hillsides and rocky ledges (Cobb 1984). Open turfy, gravelly or ledgy slopes, shores and meadows, chiefly calcareous (Fernald 1970).

Associated Ecological Communities

  • Calcareous talus slope woodland (guide)
    An open or closed canopy community that occurs on talus slopes composed of calcareous bedrock such as limestone or dolomite. The soils are usually moist and loamy; there may be numerous rock outcrops.

Associated Species

  • Acer spicatum (mountain maple)
  • Arabidopsis lyrata
  • Botrychium lunaria (common moonwort)
  • Cryptogramma stelleri (slender cliff-brake, Steller's cliff-brake)
  • Dryopteris marginalis (marginal wood fern)
  • Fragaria virginiana
  • Mitella diphylla (two-leaved mitrewort, two-leaved bishop's-cap)
  • Thuja occidentalis (northern white cedar, arbor vitae)


New York State Distribution

This fern is only known from Onondaga County.

Global Distribution

One of the most widespread moonworts in North America, occurring in practically all parts of Canada and Alaska and throughout the western United States, south to Arizona, and in all the US/Canadian border states.

Identification Comments

General Description

Mingan moonwort is a very small perennial fern with a single aboveground frond. The frond may reach about 8 inches tall but is usually smaller and can be seen until middle or late summer. It is divided into two leaves above a common stalk. The sterile leaf is usually a deep, dull green and somewhat fleshy. It has up to 10 usually well separated pairs of leaflets (pinnae). The pinnae are variable but generally narrowly fan-shaped. The top edges are rounded and smooth but they can be broader and may be lobed or have cut edges. The fertile leaf is longer than the sterile leaf with branches that bear grape-like sporangia. Spores germinate underground and develop into tiny, non-photosynthetic gametophytes which depend on an fungus for nourishment.

Identifying Characteristics

Mingan moonwort is a very small perennial fern with a single aboveground frond. Frond 2-10 cm tall, visible until middle or late summer. Sterile leaf is usually a deep, dull green and somewhat fleshy. Pinnae to 10 pairs, horizontal to slightly spreading, approximate to remote but not overlapping. Pinnae variable, generally narrowly fan-shaped or ovate, sides somewhat concave, margins nearly entire, shallowly crenate, occasionally pinnately lobed or divided, apex rounded, venation like ribs of a fan with a short midrib. Fertile leaf 1-3-pinnate, 1.3-2.4 times the length of the sterile leaf.

Best Life Stage for Proper Identification

This fern is best identified when the leaves are fully formed.

Similar Species

Botrychium minganense is most easily confused with Botrychium lunaria, Botrychium campestre, and Botrychium simplex. The pinnae of Botrychium lunaria are broader, more fan shaped and overlap. Botrychium campestre has a shorter and more branched fertile leaf and the pinnae of the sterile leaf are often deeply divided at the top. Its leaves can only be seen in the spring. In Botrychium simplex the upper pinnules are somewhat fused together and not separate. The fertile leaf often arises from near the ground level. Botrychium matricariifolium pinnules are long and narrow with a central midrib and secondary segments. Reliable field determination of moonworts depends on the careful use of technical keys and comparison with silhouette outlines of verified specimens. Identification can be complicated because there is often a high degree of morphological variability between individuals in a population and between populations of the same species. Several species may grow together at the same site, and the few diagnostic characters may not be apparent in small plants.

Best Time to See

Mature fronds of this plant are visible from June to August. This should be the time of year when surveys for this species are conducted.

  • Vegetative
  • Fruiting

The time of year you would expect to find Mingan Moonwort vegetative and fruiting in New York.

Mingan Moonwort Images


Mingan Moonwort
Botrychium minganense Victorin

  • Kingdom Plantae
    • Phylum Filicinophyta
      • Class Ophioglossopsida
        • Order Ophioglossales
          • Family Ophioglossaceae (adder's-tongue family)


  • Botrychium lunaria ssp. minganense (Victorin) Calder & Taylor
  • Botrychium lunaria var. minganense (Victorin) Dole

Additional Resources

Best Identification Reference

Flora of North America Editorial Committee. 1993. Flora of North America, North of Mexico. Volume 2. Pteridophytes and Gymnosperms. Oxford University Press, New York. 475 pp.

Other References

Cobb, Boughton. 1984. A field guides to ferns and their related familes, Northeastern and Central North America with a section on species also found in the British Isles and western Europe. The Peterson Field Guide Series. Boston, New York.

Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.

Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.

Lellinger, David B. 1985. A Field Manual of the ferns and fern-allies of the United States and Canada. Smithsonian Institution, Washington, D.C. 389 Pp.

Mitchell, Richard S. and Charles J. Sheviak. 1981. Rare Plants of New York State. Bull No. 445. New York State Museum. Univ. of New York. State Ed. Department Albany, NY.

New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.

New York Natural Heritage Program. 2024. New York Natural Heritage Program Databases. Albany, NY.

Wagner, Florence S. 1988. Moonworts Recently Discovered in the Great Lakes Area. Fiddlehead Forum 15(1): 2-3.

Wagner, Jr., W.H. and F.S. Wagner. 1990. Moonworts (Botrychium subg. Botrychium) of the Upper Great Lakes Region, USA and Canada, with Descriptions of Two New Species. Contr. Univ. Mich. Herb. 17: 313-325.

Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://newyork.plantatlas.usf.edu/, Albany, New York


About This Guide

Information for this guide was last updated on: June 22, 2005

Please cite this page as:
New York Natural Heritage Program. 2024. Online Conservation Guide for Botrychium minganense. Available from: https://guides.nynhp.org/mingan-moonwort/. Accessed April 16, 2024.