Dryopteris carthusiana (Spinulose wood fern)

Dryopteris carthusiana (Vill.) H.P. Fuchs

Spinulose wood fern, spreading wood fern, toothed wood fern, narrow buckler fern

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Pteridophyta	Ferns
Class	Filicopsida	“Leptosporangiate” (has to do with how their spores form) ferns—includes most ferns
Order	Polypodiales	Polypod ferns
Family	Dryopteridaceae	Wood ferns (about 70% of the ferns)
Genus	Dryopteris	From Greek dryas, “oak,” and pteris, “fern,” in reference to the presence of some species of wood ferns in woodland areas populated with oaks
Species	carthusiana	For Johann Friedrich Cartheuser, physician, naturalist, anatomist, botanist, pathologist, chemist, pharmacist, and prolific author

About plant names...

Spinulose wood fern is named because its leaves have tiny spinules (spines) on their tips. The genus Dryopteris translates to ”fern of the oak wood,” and the species carthusiana honors Johann Friedrich Cartheuser, a polymath who died in 1777. Cartheuser was a physician, naturalist, anatomist, botanist, pathologist, chemist, pharmacist, and prolific author.

Identification: These ferns grow in uneven clumps or solitary fronds, and are 12-36" (30-91 cm) high. They prefer moist habitats. Fronds are 6-30" (15-76 cm) long and 4-12" (10-30 cm) wide. Each frond consists of primary leaflets (pinnae), composed of secondary leaflets (pinnules), which in turn are sometimes composed of tertiary leaflets, for which I couldn’t find a fancy name. This triple hierarchy makes these ferns (along with many others) tripinnate. And just to make sure you’re still paying attention, the tertiary leaflets are replete with little serrations called spinules, making spinulose wood ferns practically quadropinnate, a word that I’m pretty sure doesn’t exist. Leaflet bottoms contain the ferns’ reproductive structures, or sori, which are small, brown rounded mounds. At close range, the sori look like microminiature shrubs, about ¹/₁₆" (2 mm) in diameter.

Online References:

Dryopteris carthusiana on Earl J.S. Rook's Flora, Fauna, Earth, and Sky ... The Natural History of the Northwoods

Dryopteris carthusiana on the Connecticut Botanical Society's Connecticut wildflowers site

Dryopteris carthusiana at Ontario Ferns

References:

Cobb, Boughton, Farnsworth, Elizabeth & Lowe, Cheryl, Peterson Field Guides: A Field Guide to Ferns and Their Related Families of Northwestern and Central North America, Houghton Mifflin Company, 2005, p. 132