GYMNOCARPIUM DRYOPTERIS (L.) Newman

var. DISJUNCTUM (Ledeb.) Ching

Common Oak Fern

 

 

FAMILY: Aspleniaceae (Polypodiaceae)

SYNONYMS: Dryopteris disjuncta (Ledeb.) C.V. Morton Phegopteris dryopteris (L.) Fee

HABIT: Perennial from a slender rhizome, fronds deciduous, 0.4-5 dm.; sporulating June-September.

SIMILAR SPECIES: This delicate fern resembles depauperate beech ferns (Phegopteris spp.), which also grow in similar habitats. However, the fronds of oak fern are definitely ternate, while those of beech ferns are pinnate.

TOTAL RANGE: Greenland to Ont., s. to NJ, VA, OH, MI, WI, and MO; the typical variety occurs to the west and northwest of this range.

STATE RANGE: There are post-1960 collections from 5 counties: Columbiana, Erie, Jefferson, Lorain, and Mahoning. There are pre-1960 specimens from 5 other counties: Ashtabula, Lake, Licking, Portage, and Wayne.

STATE STATUS: 1980 to present: Threatened.

HABITAT: Mesic woods and slopes, often with hemlock.

HAZARDS: Drying of habitat by removal of forest canopy; soil compaction.

RECOVERY POTENTIAL: Probably poor.

INVENTORY GUIDELINES: Collect complete, mature specimens.

COMMENTS: This species may be overlooked because of its delicate appearance or misidentified as other species. It does appear, however, to be limited to northeastern Ohio, where suitable habitats are rarely undisturbed.
Like many other fern taxa, this plant has undergone radically different treatments, having been placed in three separate genera (see Synonyms). The treatment used here is one followed by most recent authors.

SELECTED REFERENCES:

 

Oliver, J.C. 1972. Preliminary systematic studies of the oak ferns: chromatography and electrophoresis. Amer. Fern Jour. 62: 16-20.

Wagner, W.H., Jr. 1966. New data on North American oak ferns, Gymnocarpium. Rhodora 68: 121-138.

 

 

Division of Natural Areas and Preserves

Ohio Department of Natural Resources

Created: 3/1982 Allison W. Cusick

Database Code: SPEF.296