Common Oak Fern vs Pacific Oak Fern

Gymnocarpium dryopteris compared with Gymnocarpium disjunctum

Key Differences

• Common Oak Fern is Critically Endangered while Pacific Oak Fern is Not Evaluated.

Taxonomic Classification

Rank	Common Oak Fern	Pacific Oak Fern
Kingdom same	Plantae (Plants)	Plantae (Plants)
Phylum same	Tracheophyta	Tracheophyta
Class same	Polypodiopsida (Polypodiopsida)	Polypodiopsida (Polypodiopsida)
Order same	Polypodiales (Polypodiales)	Polypodiales (Polypodiales)
Family same	Cystopteridaceae	Cystopteridaceae
Genus same	Gymnocarpium	Gymnocarpium
Species	Gymnocarpium dryopteris	Gymnocarpium disjunctum

Evolutionary Relationship

Common Oak Fern and Pacific Oak Fern share a common ancestor at the Genus level: Gymnocarpium.

Conservation Status

Common Oak Fern

CR — Critically Endangered

Pacific Oak Fern

NE — Not Evaluated

Physical Characteristics

Attribute	Common Oak Fern	Pacific Oak Fern
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Common Oak Fern

Habitat

Found across multiple habitat types including temperate broadleaf and mixed forests, temperate coniferous forests, and boreal forests and taiga, among 4 distinct biome types within the Palearctic biogeographic realm. Populations are also found in montane and highland environments at higher elevations.

Range

Found across Europe (6 countries) and North America (Canada, United States). Currently classified as Critically Endangered on the IUCN Red List, this species faces significant conservation challenges across its range.

Pacific Oak Fern

Habitat

Typically found in moist, shaded forest floors and tropical canopies.

Range

Distributed across Canada, Norway, and United States.

Common Oak Fern

<em>Gymnocarpium dryopteris</em>, the common oak fern, is a delicate terrestrial fern in the family Cystopteridaceae (or Woodsiaceae, depending on classification). Despite its common name, the species is not specifically associated with oak trees; rather, it typically grows in cool, moist, shaded environments including boreal and mixed forests, rocky woodland slopes, stream banks, and shaded cliff faces. <em>Gymnocarpium dryopteris</em> spreads by rhizomes and forms low, spreading colonies with characteristic triangular, three-pinnate fronds that emerge from a slender creeping rootstock. Its geographic range spans Europe and North America, with populations in cool temperate and boreal zones. The species is currently assessed as Critically Endangered in certain regional assessments, suggesting that particular populations face severe decline, likely due to habitat loss, forest fragmentation, and altered hydrology, even if the species retains a broader global range. Biological traits such as lifespan, body size, and diet remain poorly documented at a standardized population level. <em>Gymnocarpium dryopteris</em> is a characteristic indicator of undisturbed cool woodland habitats and is valued for both its ecological role in forest understoreys and its aesthetic appeal.

Shared Countries

Both species can be found in 3 countries:

🇨🇦 Canada 🇳🇴 Norway 🇺🇸 United States