Connecticut Plants
Slender Fragile Fern (Mackay's Brittle Fern)
Cystopteris tenuis (Michx.) Desv.

Slender fragile fern is very similar to fragile fern; until recently, they were considered to be varieties of the same species.

  • Synonyms: Cystopteris fragilis (L.) Bernh. var. mackayi G. Lawson
  • Family: cliff fern (Woodsiaceae)
  • Habitat: shaded rocky areas, occasionally on the forest floor
  • Height: fronds 6-14 inches long
  • Location of spores: undersides of leaflets
  • Petiole (leaf stalk): Slender, smooth with a few scales near base. Dark brown or black at base, becoming yellow or green above.
  • Growth pattern: asymmetric clump
  • Persistence: deciduous
  • Origin: native
Cystopteris tenuis (Michx.) Desv.
Cystopteris tenuis (Michx.) Desv.

A frond of slender fragile fern.

Cystopteris tenuis (Michx.) Desv.

Underside of a frond, showing the sori (spore-bearing structures).