- Scientific name: Lygodium palmatum (Bernh.) Sw.
- Species of Greatest Conservation Need (MA State Wildlife Action Plan)
- Special Concern (MA Endangered Species Act)
Description
Image credit: Bruce Sorrie (NHESP)
Climbing fern, Lygodium palmatum, in the curly grass family (Schizaeaceae) does not have the characteristic overall shape of most ferns. It is an evergreen, ivy-like plant which sprawls over the ground or climbs clockwise short distances up shrubs and coarse herbs. In very favorable conditions, climbing fern may carpet up to an acre of more of the forest floor. The rootstalk is black, wiry, widely creeping, and branching. The root sends up a row of twining delicate fronds to a height of 0.9-1.5 m (3-5 ft). The pinnae (fern equivalent of leaflets) are a forking stalk, with each stalk ending in a palmately lobed yellow-green blade about 3-6 cm (2 in) across. The fertile blades are at the tips of the fertile pinnae and are tiny, palmate, and produce spores on the underside. The gross morphology of this fern distinguishes it from all other species in Massachusetts.
Life cycle and behavior
This is an evergreen species. It produces spores which are distributed by the wind.
Population status
Climbing fern is listed under the Massachusetts Endangered Species Act as Species of special concern. All listed species are protected from killing, collecting, possessing, or sale and from activities that would destroy habitat and thus directly or indirectly cause mortality or disrupt critical behaviors. There are currently 35 occurrences in the state verified since 1999 found in Barnstable, Bristol, Franklin, Hampden, Hampshire, Middlesex and Worcester Counties.
Distribution in Massachusetts
1999-2024
Based on records in the Natural Heritage Database
Distribution and abundance
Climbing fern occurs from southern New Hampshire and northwestern Vermont west to Michigan, and south to Georgia and Alabama. It is considered imperiled or vulnerable in all but 4 states. In New England, it is considered critically imperiled in New Hampshire, Vermont, and Rhode Island; and vulnerable in Connecticut and Massachusetts. It is not known from Maine.
Habitat
Climbing fern grows in moist pine-oak-maple woods with an open understory, in moist thickets, and along stream margins. This plant prefers acidic soils that are sandy and rich in humus but nutrient-poor. Regenerating woodlands and powerline corridors also provide habitat for this species in Massachusetts. The plants prefer partial to full sun, and do not do well under a dense canopy.
Healthy habitats are vital for supporting native wildlife and plants. Explore habitats and learn about conservation and restoration in Massachusetts.
Threats
In the 1800s, when climbing fern was much more common, it was very popular as a decoration and commercial collection contributed to its decline. The first plant protection law in the United States was passed in Connecticut in 1869 specifically to protect this species. Legal protection helped alleviate the collection problem. However, loss of habitat through expansion of agriculture and development continued as the major factor contributing to the species decline. Other threats include maturation of woodlands which overshades the species, increases in invasive plants also lead to its decline, particularly multiflora rose (Rosa multiflora), Japanese barberry (Berberis thunbergii), and glossy buckthorn (Frangula alnus) can all grow in the same habitat and will grow to densities that overshade climbing fern.
Although climbing fern may be abundant where it is found, populations are rare and localized. Seemingly appropriate habitat for climbing fern is fairly common in Massachusetts; however, for unknown reasons, climbing fern occurs in only a very few of these areas.
Conservation
Regular surveys are important for this species, as the number of fronds and their locations within populations will change. At a minimum, surveys should occur every 10 to 15 years. The best time to survey for climbing fern is in the spring after snow melt but before other plants leaf out.
Monitoring and removal of competing vegetation, particularly non-native invasive species, should be considered as a management strategy where appropriate. All active management of rare plant populations (including invasive species removal) is subject to review under the Massachusetts Endangered Species Act and should be planned in close consultation with MassWildlife’s Natural Heritage & Endangered Species Program.
The ecological needs of this species are not fully understood. Research needs for climbing fern include specific habitat needs as there appears to be more available habitat than populations.
References
Cobb, Boughton, Elizabeth Farnsworth, and Cheryl Lowe, 2005. Ferns of Northeastern and Central North America, Second Edition. Houghton Mifflin Company, New York, NY.
NatureServe. 2025. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. Accessed: 5/27/2025.
POWO (2025). Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Published on the Internet; https://powo.science.kew.org/ Accessed: 5/27/2025.
Sessa, Emily B. 2024. Ferns, Spikemosses, Clubmosses, and Quillworts of Eastern North America. Princeton University Press, Princeton, NJ.
Contact
| Date published: | May 6, 2025 |
|---|