Foliage Gardens - Fern Nomenclature

by Sue Olsen




Crosier or fiddlehead - an unfurling frond

Entire - an undivided frond

Fertile - spore bearing

Frond - a complete leaf which is made up of the:

Stipe - a stalk or petiole which supports the blade

Blade - the leafy portion of the frond

Pinna (Plural pinnae) - a primary division of the frond - a leaflet

Pinnate - once divided; bipinnate - twice divided; tripinnate - thrice divided

Pinnule - a division of a pinna - a segment

Rhizome - the growth center of the fern - roots below and fronds above

Sorus (plural sori) - a fruit dot containing spores

Spores - the fern's reproductive unit.


Noting the name, meaning, number and distribution of species and a brief description.

Adiantum aleuticum 'Subpumilum'

ADIANTUM - maidenhair - Greek - to shed water - 200 species, mostly tropical - worldwide - stipe brittle frequently black or red-black; fronds lacking a distinct midrib; foliage delicate, lacy, often drooping; thin textured; pinna fan or wedge shaped; sori around the outer edges covered with a false indusium of curled segments; evergreen and deciduous.

ARACHNIODES - spider like - 40 species - mostly temperate - evergreen - closely related to Polystichum and Dryopteris - stipes greenish or straw colored; rhizome frequently spreading; evergreen; tall foliage usually spiny; sori central; indusium kidney shaped.

ASPLENIUM - without spleen referring to a reputation for curing disorders of the spleen - 700 species - many hybrids - worldwide - usually evergreen; small with dark stipes; foliage varied - bird’s nest fern to A. trichomanes; stipes short; sori in herringbone pattern; indusium attached to a vein opening on one side (clamshell fashion).

ATHYRIUM - to sport - 180 species - temperate and tropical; deciduous; stipes usually stout and succulent; green or straw colored and long; fronds long thin textured; sori central with half moon shaped indusium opening along one side.

BLECHNUM - Greek name for a type of fern - 220 species - temperate and tropical; evergreen and sub-evergreen leathery and dimorphic (fertile and sterile fronds different); fertile fronds erect; sori linear occupying entire space from midrib to out edge of fertile frond segment; indusium linear with central lengthwise opening (slit down the middle)!

CHEILANTHES - lip fern - 150 species - temperate, tropical and arid - stipes short, brittle, dense in growth; tufted; often scaly or hirsute; foliage evergreen also hairy or with scales on the underside; pinnae beadlike; prefers dry rocky locations; will curl in drought revive with moisture; sori marginal covered with reflexed edge of pinna but not continuous around the edge.

CRYPTOGRAMMA - hidden sori - - 11 species - mostly temperate; small evergreens with light colored stipe; rock loving; dimorphic with fertile fronds erect; sori under overlapping margins.

CYRTOMIUM - arching - 15 species - temperate & sub tropical; stipe stiff; evergreen pinnate leathery foliage; bold; low light; smoke and drought tolerant; sori central with peltate (umbrella like) indusium.

CYSTOPTERIS - bladder fern - 18 species - temperate; small delicate, common; deciduous; light green; spore black when unripe; sori on veins with hood-like covering.

DRYOPTERIS - wood fern - 250 species (my original research indicated 1213 species - the botanical splitters have been at work) - worldwide; evergreen and deciduous, small to very large; sturdy; usually divided - often finely so; hybridizes frequently; sori central with kidney shaped indusium.

GYMNOCARPIUM - naked fruit - no indusium - few species - temperate; stiff brittle stipe; horizontal triangular fronds; deciduous; thin texture; spreading via underground rhizomes; sori round.

LYGODIUM - twining - 39 species - mostly tropical; climbing ferns; sterile portion evergreen; fertile portion a continuation of the main stem & deciduous; sori on underside of fertile segments.

MATTEUCCIA - named for an Italian physicist; 3 species - temperate; very large deciduous plumy fronds; dimorphic with sterile fronds to 5'; fertile fronds to 2' with sori in hard brown pods.

NOTHOLAENA - cloak fern - false indusium - 25 species - closely allied with Cheilanthes and Pellaea - mostly arid loving small ferns with proportionately long stipes; erect inhabitants of rocky dry places; foliage frequently with hairs, scales or waxy undercoating; sori hidden in wax, scales or around edges.

OSMUNDA - Osmund - Thor - Scandinavian god of war - 10 species - mostly temperate; large deciduous primitive ferns; moisture loving; spore not on underside of leaf but on separate stalks from rachis (flowering fern).

PELLAEA - dark - dusky - 85 species - temperate & tropical; rigid stiff stipe & frond; evergreen; often with powdery or waxy coverings; stipe dark purple; foliage usually blue; simply divided; rock ferns with long wiry roots; sori marginal; continuous under rolled edges of pinna.

PHYLLITIS - leaf - often listed as Asplenium - 8 species - many varieties - temperate; stipes very short; simple undivided foliage; evergreen long fronds; sori linear; prominent like rows of buttonholes opening through central split.

POLYPODIUM - many footed - 100 species (formerly 1127 species - see Dryopteris) - widely distributed; prominent creeping rhizome; often epiphytic; evergreen leathery leaves; usually pinnate; large round sori; no indusium.

POLYSTICHUM - many stitches - in reference to the spore pattern on the under leaf; 180 species - worldwide; mostly temperate; sturdy evergreen growth in a single crown or cluster; pinnate to finely divided foliage; short stipes; frequently with shiny foliage with bristly toothed edges; sori covered with peltate indusium.

WOODSIA - named for botanist Joseph Woods - 37 species - temperate to arctic; small deciduous ferns in woods and on rocks; spores brown on the outer edges of pinna; indusium fist like opening star like from under the sporangia.

WOODWARDIA - named for botanist Thomas Woodward - 14 species - mostly temperate - acid soil; extremely large coarse evergreen & deciduous ferns; sori in long lines like strings of sausage (hence chain fern); sori linear opening in a central split.

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