Dryopteris carthusiana

Dryopteris carthusiana
Scientific classification
Kingdom:	Plantae
Division:	Pteridophyta
Class:	Pteridopsida
Order:	Polypodiales
Family:	Dryopteridaceae
Genus:	Dryopteris
Species:	D. carthusiana
Binomial name
Dryopteris carthusiana (Vill.) H.P. Fuchs

Young sori on the frond underside.

Dryopteris carthusiana (Vill.) H.P. Fuchs (syn. D. spinulosa (O.F. Muell.) O. Kuntze) is a species of fern native to damp forests throughout the Holarctic Kingdom. It is known as the Narrow buckler fern in the United Kingdom, and as the Spinulose wood fern in North America.

It is a tetraploid of hybrid origin, one parent being Dryopteris intermedia, known in North America as the intermediate wood fern, and an unknown, apparently extinct species dubbed Dryopteris semicristata, which is also the presumed parent of the hybrid-origin Dryopteris cristata.

This fern is often confused with several other wood fern species, including D. intermedia, D. campyloptera, and D. expansa. It especially extensively shares the range of D. intermedia, but the two may be distinguished by the innermost pinnule on the bottom side of the bottom pinna: this pinnule is longer than the adjacent pinnules in D. carthusiana, but shorter or even in D. intermedia. D. carthusiana is a sub-evergreen species, its fronds surviving mild winters but dying back in harsh winters.

A nature print of Dryopteris carthusiana

References

• USDA PLANTS Profile
• Dryopteris carthusiana in Flora of North America
• British Scanned Ferns: Dryopteris carthusiana