Gymnocarpium jessoense — 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.
From the 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.