Gymnocarpium jessoense (Koidzumi) Koidzumi
Nahanni oak fern
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New England Distribution
Adapted from BONAP data
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
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Nahanni oak fern has a distribution that includes Canada and some northern states. In New England it is a very rare fern of high-pH cliffs and talus slopes in Vermont.
Cliffs, balds, or ledges, ridges or ledges, talus and rocky slopes
- New England state
- Features of leaves
- there are no special features on the leaves
- New England state
- Specific habitat
- cliffs, balds, or ledges
- ridges or ledges
- talus or rocky slopes
Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)
New England Distribution and Conservation Status
- New Hampshire
- Rhode Island
Exact status definitions can vary from state to state. For details, please check with your state.
- unrankable (S-rank: SU)
Native to North America?
Sometimes Confused With
- Gymnocarpium dryopteris:
- leaf essentially glabrous, and basal leaflets and basiscopic leafules spreading, not curving toward plant apex (vs. G. jessoense, with the leaf stipitate-glandular on petiole, rachis, and abaxial blade surface, and basal leaflets and basiscopic leafules curving toward apex of plant).
- Gymnocarpium continentale (Petrov) Pojark
Notes on Subspecies and Varieties in New England
Our subspecies is Gymnocarpium jessoense (Koidzumi) Koidzumi ssp. parvulum.
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Information from Dichotomous Key of Flora Novae Angliae
2. Gymnocarpium jessoense (Koidzumi) Koidzumi ssp. parvulum Sarvela NC
Nahanni oak fern. Gymnocarpium continentale (Petrov) Pojark • VT. High-pH rock of cliffs and talus slopes.