Identifying Southwest Florida's Ferns

Pinnate-pinnatifid Frond


To identify a pinnate-pinnatifid fern, begin with the first question and continue until you get a "yes" answer. If one question leads you to more questions, follow the same procedure. There are many ferns with pinnate-pinnatifid fronds; you'll need to look closely to tell them apart. Fern speak: pinna (plural pinnae) are the leaf-like cuts on the frond and pinnules are the cut "lobes" on each pinna

1. Are there small tufts of rusty-brown hairs at the base of each pinna where the midrib of the pinnae meets the midrib of the frond (no sori on pinnae but on a separate spore-bearing frond)? YES, or

1. Are the bases of each pinnae missing tufts of rusty-brown hair, and are the sori on the underside of the pinnae ? YES

There are no more pinnate-pinnatifid frond questions in this section. If it is a pinnate-pinnatifid frond, the answer to one of these two questions will be a "yes."

Pinnate-pinnatifid Fronds, no tufts of hair at base of pinnae, sori on pinnae

2. Is the upperside of the pinnae smooth with no or very few hairs? YES, or

2. Is the frond somewhat to definitely hair (it feels velvet-like)? YES

There are no more pinnate-pinnatifid frond questions in this section. If it is a pinnate-pinnatifid frond with no tufts of hair at the base of the pinnae and which has sori on the underside of the frond, the answer to one of the above two questions will be a "yes."

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Pinnate-pinnatifid fronds, upperside of pinnae smooth

Fern speak: a pinnule is the cut segment on each pinna; sori are the small, brown roundish spore cases found along the underside of the frond

3. Are the pinnules cut halfway to the midvein, rounded, and shiny on the top (sori are toward the edges)? YES, or

3. Are the pinnules cut almost all the way to the midvein (sori are at the midvein)? YES, or

3. Are the pinnules wide, dark green, toothed, and the terminal (tip) pinna so deeply lobed that it looks almost like three pinnae? YES

There are no more pinnate-pinnatifid frond questions in this section. If it is a pinnate-pinnatifid frond whose upper sides are smooth, the answer to one of the above two questions will be a "yes."

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Pinnate-pinnatifid Fronds, upperside smooth, pinnules cut to (or nearly to) the midvein and sori along midvein

Fern speak: pinna (plural: pinnae) is the little leaf-looking part of the frond; pinnules are the "lobes" on the pinnae

4. Are the pinnae small and very narrow (they look a bit like a tuning fork) with only a few hairs on top? YES, or

4. Are the pinnules rounded and the pinnae dark green? YES, or

4. Do the pinnules taper to a point, are the lobes short and blunt, and are there chain-like veins on the underside by the midvein? YES, or

4. Is the lower surface of the pinnae conspicuously resin-dotted and the rhizome erect? YES

There are no more pinnate-pinnatifid frond questions in this section. If it is a pinnate-pinnatifid frond with a smooth upperside, cut pinnules, and sori along the midvein, the answer to one of the above four questions must be a "yes."

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Pinnate-pinnatifid Fronds, no tufts of hair at base of pinnae, frond somewhat to definitely hairy

Fern speak: the blade is the top part of the frond with green leafy things on it

2. Is the blade triangular shaped (the pinnae toward the bottom are longer)? YES, or

2. Is the blade more egg-shaped or oval (the pinnae toward the bottom get shorter)? YES

There are no more pinnate-pinnatifid frond questions in this section. If it is a pinnate-pinnatifid frond with no tufts of hair at the base of the pinnae and the frond is somewhat to definitely hairy, the answer to one of the above two questions will be a "yes."

Pinnate-pinnatifid Fronds, no tufts of hair at base of pinnae, frond somewhat to definitely hairy, blades triangular shaped

2. Are the lobes separated, hairy all over, and come to slight points at the tip? YES, or

2. Are the lobes really close and and slightly rounded at the tip? YES

There are no more pinnate-pinnatifid frond questions in this section. If it is a pinnate-pinnatifid frond with no tufts of hair at the base of the pinnae and the frond is somewhat to definitely hairy, the answer to one of the above two questions will be a "yes."

 

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Osmunda cinnamonea

(Cinnamon Fern)

pinnate-pinnatifid frond

Description
blades with a tuft or rusty hairs at the base of each pinna; stipe and rachis with abundant cinnamon hairs, especially in spring; blade light green and somewhat glossy; 36-48" tall and 5-10" wide; fertile fronds are separate spore stalks; pinnule tips rounded
Rhizome
long-creeping; fronds distant
Spores do not appear on leaves but on separate leafless frond (center and far right); spore-bearing frond grows from rhizome separate from sterile fronds
Veins free, forking
Growth swamps and other wet, moist soils
Similar sterile frond looks like a Thelypteris, but no Thelypteris has the rusty hairs at the base of each pinna; Osmunda regalis (Royal Fern) is the only other fern that bears spores on a unique structure rather than the pinna underside

Thelypteris interrupta

(Shiny Thelypteris, Swamp Shield Fern, Hottentot Fern)

pinnate-pinnatifid frond

Description
fronds shiny on top and dark green -- never dull and never with hairs; spaced distantly; tough; pinnae 30-50" tall, 3/8-1/2" wide; pinnules widely lobed; pointed tips on pinna especially notceable on the "tail" at the top of the frond
Rhizome
long-creeping; black, nearly naked, underground
Spores sori form a continuous meandering line along the edge of the pinna; much closer to margins than to midvein of pinnule (photo above right)
Veins lowest veins of neighboring pinnules touch, forming a triangle, with another vein going from the triangle to the cut between the pinnules; only the Thelypteris dentata is similarly veined
Growth standing shallow water and very moist soil; in full sun or partial shade
Similar

Thelypteris palustris (Marsh Fern)

  • pinnae very narrow, 12 times longer than wide

Dryopteris ludoviciana (Florida Shield Fern)

  • dark green pinnae
  • tan scales on stipe and rachis

Woodwardia virginica (Chain Fern)

  • pinnae lobes short and blunt

Thelypteris palustris

(Marsh Fern)

pinnate-pinnatifid frond

Description
lacy delicate appearance; fronds 18-30" tall; pinnae don't taper near base but stop abruptly -- really long stipe: fertile fronds have segments inrolled; pinnules not lobed
Rhizome
long creeping; fronds distant from each other
Spores medial but appearing closer to edge because of the curled margin; about 8 sori on each side of the midvein
Veins some forked between the pinnule midveins and the margins
Growth wet meadows and swamps -- a wide variety of wet situations
Similar

Dryopteris ludoviciana (Florida Shield Vern)

  • dark green pinnae; tan scales on stipe and rachis

Woodwardia virginica (Chain Fern)

  • pinnae lobes short, blunt, and wider
  • veins netted

Thelypteris interrupta (Shiny Thelypteris)

  • pinnae very shiny on top and much wider
  • veins run from base to cut between pinnules

Dryopteris ludoviciana

(Florida Shield Fern, Southern Wood Fern)

pinnate-pinnatifid frond

Description
lower pinnae strikingly larger and wider than upper pinnae; lustrous dark green, leathery; rhizome, stipe, and rachis with tan scales; stipe 1/4 frond length; fertile pinnae noticeably contracted; pinnule edges appear scalloped
Rhizome
short-creeping; horizontal, has tan scales
Spores fertile fronds bear sori only in upper half; fertile pinnae much narrower than sterile ones; sori round, 2-3 on each side of midvein
Veins free
Growth fwet woods, swamps, maargins of cypress swamps
Similar

Thelypteris palustris (Marsh Fern)

  • pinnae very narrow, 12 times longer than wide

Thelypteris interrrupta (Shiny Thelypteris)

  • pinnae very shinyt on top
  • veins run from base to cut between pinnules

Woodwardia virginica (Chain Fern)

  • pinnae lobes short and blunt

Woodwardia virginica

(Chain Fern, Virginia Chain Fern)

pinnate-pinnatifid frond

Description
pinnae alternate; thin fronds 1.5-2" wide; pinnae lobes triangular-shaped, short, blunt, smooth-margined; fertile and sterile fronds alike; pinnae deeper cut than Thelypteris interrupta
Rhizome
long-creeping, slender
Spores linear on both sides of pinna midrib and along pinnule midrib (photo above right)
Veins areas enclosed by veins appear chain-like in a single series along leaflet midveins; then, free to margin (photo above center)
Growth flikes acidic bogs and swamps; prefers edges to open areas around the bases of trees or among cypress knees; the first ferns to come back after fire in pine areas
Similar

Thelypteris palustris (Marsh Fern)

  • pinnae very narrow, 12 times longer than wide
  • lobes more spaced

Thelypteris interrupta (Shiny Thelypteris)

  • pinnae very shiny on top
  • veins run from base to cut between pinnules

Drypteris ludoviciana (Florida Shield Fern)

  • dark green pinnae
  • tan scales on stipe and rachis

Thelypteris kunthii

(Southern Shield Fern, Wood Fern, Widespread Maiden Fern)

pinnate-pinnatifid frond

Description
pinnules taper to a point but not as obvious as T. interrupta (right photo); stems and underside hairy, upperside somewhat hairy -- feels velvet-like; pinnae lobes separated; base pinnules long and don't taper in; tip tapers to a noticeable "tail"; 22-45" tall, 6-12" wide
Rhizome
short-creeping to long-creeping
Spores 3-5 spores parallel and on each side of the pinnule midvein (photo above right)
Veins free
Growth terrestrial, preferring moist or dry woods
Similar

Thelypteris dentata (Downy Shield Fern)

  • pinnules rounded
  • hairs on blade uniformly short
  • stipe and rachis purplish

Thelypteris dentata (rare)

(Downy Shield Fern)

pinnate-pinnatifid frond

Description
pinnules rounded; pinnae hairy on both upper and lower surfaces -- feels velvet-like; hairs uniformly short, shorter than sporangia; fronds are thin, a distinctive dull dark green; lower stems of fronds not covered with hairs; pinnae lobes closely spaced; 24-50" tall, 6-14" wide; stipe and rachis purplish
Rhizome
short-creeping
Spores 3-5 spores parallel and on either side of pinnule midvein
Veins free; base veins of each pair of adjacent pinna lobes united into one vein which runs to the edge of the pinna, making a triangle
Growth moist woods
Similar

Thelypteris kunthii (Wood Fern)

  • pinnules taper to a slight point
  • hairier

Thelypteris interrupta (Shiny Thelypteris)

  • only other fern with similar vein pattern, but it is not hairy and is much more common

Tectaria heracleifolia

(Broad Halbred Fern)

pinnate-pinnatifid frond

Description
shiny dark green fronds to 1-1/2 to 2 feet tall; 1-3 pairs of pinnae below, lowermost often deeply lobed; terminal pinnae deltoid (three distinguishable lobes) and toothed; pinnae margins often coarsely toothed
Rhizome
short-creeping
Spores conspicuous and numerous on the lower surfaces of the pinnae in a single rows along either side of the veins
Veins netted
Growth prefers rocky hammocks, limestone outcrops, shaded areas
Similar

Tectaria incisa (Incised Halbred Fern) also has three-lobed terminal pinna

  • pinnae lighter green and not as noticeably toothed
  • fronds taller, to 4-5'
Notes only found in southern tip of Florida peninsula (collected in Martin, Citrus, Hernando, Broward, Dade, and Collier Counties)

Thelyptris resinifera (rare)

pinnate-pinnatifid frond


Description
frone 36-42" tall; lower surface conspicuously resin-dotted (reddish-brown); lower pinnae of blade eared (lobed); pinnules lean toward tip instead of being at nearly right angles to pinna midvein; rachis brownish below blade and yellowish above; pinnules taper at base of blade as well as at tip
Rhizome
erect, stout
Spores strongly medial
Veins free
Growth terrestrial; prefers moist or dry woods
Similar

Thelypteris interrupta (Shiny Thelypteris)

  • base pinnules don't taper in
  • sori marginal

Dryopteris ludoviciana (Florida Shield Fern)

  • base pinnules don't taper in

Thelypteris palustris (Marsh Fern)

  • base pinnules don't taper in

Thelypteris ovata (rare)

(Ovate Maiden Fern)

pinnate-pinnatifid frond

Description
frond egg-shaped rather than triangular; fronds 22-50" tall and 4-20" wide, often arching; pinnae abut 1/2 inch wide and cut 3/4 way to pinna midvein; hairy below; rachis straw-colored
Rhizome
short-creeping to long-creeping
Spores sori toward margins of pinnules
Veins free
Growth moist woods, susceptible to cold temperatures and dies back
Similar most often confused with Thelypteris kunthii, but T. ovata more lustrous above and lacks numerous hairs on top -- more coarse feeling than soft