FERN TERMINOLOGY
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.
FERN GENUS CHARACTERISTICS - A QUICK REFERENCE
Noting the name, meaning, number and distribution of species and a brief description.
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| 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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