Onoclea sensibilis L.

sensitive fern

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

The susceptibility to frost of the sterile fronds gives sensitive fern its name. It spreads rapidly and can form large colonies. The spores are not released until the spring following the season in which the fertile fronds are produced.

Habitat

Meadows and fields, shores of rivers or lakes, swamps, wetland margins (edges of wetlands)

Characteristics

Habitat
  • terrestrial
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf divisions
  • the leaf blade is compound (divided into leaflets)
  • the leaf blade is lobed
Plant growth form
the leaves grow from a rhizome growing at or below the ground
Spore-bearing leaflets
the spore-bearing fronds are dramatically different from the sterile fronds
Sorus shape
there are no sori, or they are concealed in leaf segments or hardened, capsule-like structures derived from a modified leaflet
Leaf stalk scales
the leaf stalk has scales
Leaf stalk hairs
there are no hairs on the leaf stalk
Leaf blade length
13–34 cm
Leaf vein tips
the veins go all the way to the edge of the leaf blade
Show All Characteristics
  • Growth form
    Life form
    the plant is herbaceous and terrestrial
    Life stage
    the plant is visible as a typical leaf-bearing fern (sporophyte)
    Spore-bearing leaflets
    the spore-bearing fronds are dramatically different from the sterile fronds
  • Leaves
    Features of leaves
    there are no special features on the leaves
    Leaf blade length
    13–34 cm
    Leaf blade shape
    the leaf blades are roughly triangular
    Leaf blade width
    At least 15 cm
    Leaf divisions
    • the leaf blade is compound (divided into leaflets)
    • the leaf blade is lobed
    Leaf lifespan
    the leaves drop off in winter
    Leaf stalk color
    red or red-brown to purple or black
    Leaf stalk hairs
    there are no hairs on the leaf stalk
    Leaf stalk length
    220–580 mm
    Leaf stalk relative length
    the leaf stalk is more than three quarters as long as the blade
    Leaf stalk scale location
    • the scales are present on both the lower and upper halves of the leaf stalk
    • the scales are present only on the lower half of the leaf stalk
    Leaf stalk scales
    the leaf stalk has scales
    Leaf stalk vessels
    2 bundles
    Leaf vein branching
    the secondary veins of the leaf blade split and rejoin to form a netlike pattern
    Leaf vein tips
    the veins go all the way to the edge of the leaf blade
    Leaflet relative size
    the bottom leaflets are about half as long as, to slightly longer than, the leaflets from the middle of the frond
    Leaflet stalks
    • the leaflets are stalked
    • the leaflets do not have stalks
    Lobe or leaflet length
    25–180 mm
    Lobe or leaflet pairs
    5–11
    Lobe or leaflet shape
    the lobe or leaflet is widest below the middle and tapering at both ends; lance-shaped
    Lobe or leaflet width
    15–50 mm
    Plant growth form
    the leaves grow from a rhizome growing at or below the ground
    final leaf segment margin
    the topmost lobe or leaflet of the leaf blade has a smooth or lobed edge
  • Place
    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • edges of wetlands
    • meadows or fields
    • shores of rivers or lakes
    • swamps
  • Spores or spore cones
    Sorus features
    there are no special features on the sorus
    Sorus shape
    there are no sori, or they are concealed in leaf segments or hardened, capsule-like structures derived from a modified leaflet
    Sporangia location
    the spores are hidden inside hardened, rolled-under leaf segments
    Sporangium type
    the sporangia are opaque without an annulus and usually without a stalk (leptosporangiate)
    Spore forms
    there is only one type of spore present

Wetland Status

Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)

New England Distribution and Conservation Status

Distribution

Connecticut
present
Maine
present
Massachusetts
present
New Hampshire
present
Rhode Island
present
Vermont
present

Conservation Status

Exact status definitions can vary from state to state. For details, please check with your state.

Maine
unranked (S-rank: SNR)
Massachusetts
unranked (S-rank: SNR)

Native to North America?

Yes

Sometimes Confused With

Woodwardia areolata:
vegetative leaves with leaf lobe margins minutely toothed and lacking a pale, marginal membrane (vs. O. sensibilis, with vegetative leaves with leaf lobe margins entire to undulate and with a pale, marginal membrane).

Synonyms

  • Onoclea sensibilis var. obtusilobata (Schkuhr) Torr.

Family

Onocleaceae

Genus

Onoclea

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Information from Dichotomous Key of Flora Novae Angliae

1.  Onoclea sensibilis L. N

sensitive fern. Onoclea sensibilis L. var. obtusilobata (Schkuhr) Torr. • CT, MA, ME, NH, RI, VT. 
Wet-mesic to hydric soils of fields, borders, swamps, and shorelines.