Prairie Dunewort

Botrychium campestre W.H. Wagner & Farrar ex W.H. & F. Wagner

Botrychium campestre
Diana Horton, University of Iowa Herbarium

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
Vulnerable globally, or Apparently Secure - At moderate risk of extinction, with relatively few populations or locations in the world, few individuals, and/or restricted range; or uncommon but not rare globally; may be rare in some parts of its range; possibly some cause for long-term concern due to declines or other factors. More information is needed to assign either G3 or G4.


Did you know?

Prairie dunewort was recognized as a separate species in 1986 after different-looking moonworts were discovered in Iowa prairies and sand dunes along Lake Michigan. They were overlooked before because they are so small and hard to see among grasses, come up very early in the spring, and are gone before the end of June. After examination of more specimens from around the country it was discovered that this species was also collected in Jamesville, NY, the easternmost population.

State Ranking Justification

There is one historical location in Onondaga County and a single extant occurence in Dutchess County.

Short-term Trends

This fern is historically reported from only a single county, and recently discovered this year in another county, so trends are unknown.

Conservation and Management


The primary threat to Botrychium campestre is the loss of open habitats to successional overgrowth and development.



Prairies, dunes, grassy railroad sidings, and fields over limestone (Flora of North America 1993).

Associated Ecological Communities

  • Cropland/field crops*
    An agricultural field planted in field crops such as alfalfa, wheat, timothy, and oats. This community includes hayfields that are rotated to pasture.
  • Mowed roadside/pathway*
    A narrow strip of mowed vegetation along the side of a road, or a mowed pathway through taller vegetation (e.g., meadows, old fields, woodlands, forests), or along utility right-of-way corridors (e.g., power lines, telephone lines, gas pipelines). The vegetation in these mowed strips and paths may be dominated by grasses, sedges, and rushes; or it may be dominated by forbs, vines, and low shrubs that can tolerate infrequent mowing.
  • Pastureland*
    Agricultural land permanently maintained (or recently abandoned) as a pasture area for livestock.
  • Successional old field*
    A meadow dominated by forbs and grasses that occurs on sites that have been cleared and plowed (for farming or development), and then abandoned or only occasionally mowed.

* probable association but not confirmed.


New York State Distribution

This fern was historically reported from a single location within Onondaga County, and discovered extant at a new location in Dutchess County in 2023.

Global Distribution

Botrychium campestre ranges from New York (historical) and New Brunswick west to Washington and Oregon in the U.S. and Alberta in Canada (Kartesz 1999). It ranges as far south as northeastern Colorado. Despite this wide range, populations appear to be concentrated in the upper Great Lakes region as well as western Minnesota and western Iowa to the Dakotas (Higman and Penskar 1999, Canadian Biodiversity Website 2002), with only a few widely separated occurrences elsewhere.

Identification Comments

General Description

Prairie dunewort is a very small, perennial fern with a single aboveground frond. The frond is usually only about 2 inches long and can be seen through mid-summer. It is divided into two leaves above a common stalk. The sterile leaf is very fleshy and whitish blue-green. It has five, sometimes up to nine, usually well separated pairs of upswept leaflets (pinnae). The pinnae are variable but generally very narrowly fan-shaped. The top edges of larger pinnules are usually notched into two or several segments and have small rounded or sharp teeth. The fertile leaf is the same length or slightly longer than the sterile leaf with fleshy, somewhat flattened branches that bear grape-like sporangia. Spores germinate underground and develop into tiny, non-photosynthetic gametophytes which depend on a fungus for nourishment.

Identifying Characteristics

Prairie dunewort is a very small, perennial fern with a single aboveground frond which can grow to 4 cm tall and is visible only in the spring. The sterile leaf is glaucescent, thick, and fleshy. Pinnae occur in 5 (-9) pairs, are spreading and usually remote. Pinnae are variable, mostly linear to linear-spatulate, undivided to the tip, margins are crenulate to dentate, usually notched or cleft into two to several segments, the apex is rounded to acute, venation is like the ribs of a fan without the midrib. The fertile leaf is 1-pinnate, 1-1.5 times the length of the sterile leaf.

Best Life Stage for Proper Identification

This fern is best identified when the vegetative and fruiting leaves are fully formed in late spring.

Similar Species

Botrychium campestre is most easily confused with Botrychium minganense, Botrychium lunaria, and Botrychium simplex. The pinnae of Botrychium lunaria are broader, more fan-shaped, and overlap. Botrychium minganense has a longer and less branched fertile leaf and the pinnae of the sterile leaf are not divided at the top. It's leaves can only be seen into mid to late summer. 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. Botrychium campestre usually folds up and shrinks upon drying and is very difficult to identify in this condition. A photograph of the living fern should be taken if the identification is to be confirmed at a later time.

Best Time to See

Mature fronds of this plant are visible in May and early June. Surveys should be conducted at this time of year.

  • Vegetative
  • Fruiting

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

Prairie Dunewort Images


Prairie Dunewort
Botrychium campestre W.H. Wagner & Farrar ex W.H. & F. Wagner

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

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

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.

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 University of South Florida]. New York Flora Association, 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 campestre. Available from: Accessed May 26, 2024.