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Ophioglossum pusillum — northern adder's-tongue fern

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Facts

Northern adder's-tongue looks the least fern-like of any of our New England ferns and can, therefore, be easily overlooked. This means that a careful observer, even with little or no botanical experience, can potentially add to our understanding of this plant's range. Oddly, within the vascular plants, species in this genus (Ophioglossum) have the highest known number of chromosomes.

Habitat

Anthropogenic (man-made or disturbed habitats), marshes, meadows and fields, wetland margins (edges of wetlands)

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
  • terrestrial
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf divisions
the leaf blade is entire (without lobes or dissections)
Plant growth form
the leaves grow on a stalk that also holds the sporophore, or spore-bearing leaf
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
there are no scales on the leaf stalk
Leaf stalk hairs
there are no hairs on the leaf stalk
Leaf blade length
1–12 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
    1–12 cm
    Leaf blade shape
    • the leaf blades are widest above the base, then taper broadly towards the tip (ovate)
    • the leaf blades are widest above the base, then taper narrowly towards the tip (lanceolate)
    Leaf blade tip shape
    the tip of the leaf blade is rounded
    Leaf blade width
    At least 1 cm
    Leaf divisions
    the leaf blade is entire (without lobes or dissections)
    Leaf lifespan
    the leaves drop off in winter
    Leaf stalk hairs
    there are no hairs on the leaf stalk
    Leaf stalk length
    15–190 mm
    Leaf stalk relative length
    the leaf stalk is more than three quarters as long as the blade
    Leaf stalk scale location
    there are no scales on the leaf stalk
    Leaf stalk scales
    there are no scales on the leaf stalk
    Leaf stalk vessels
    3 to 9 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
    NA
    Leaflet stalks
    • the leaflets are stalked
    • the leaflets do not have stalks
    Lobe or leaflet length
    0 mm
    Lobe or leaflet pairs
    0
    Lobe or leaflet shape
    NA
    Lobe or leaflet width
    0 mm
    Plant growth form
    the leaves grow on a stalk that also holds the sporophore, or spore-bearing leaf
    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
    • man-made or disturbed habitats
    • marshes
    • meadows or fields

  • 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 formed on a stalk (sporangiophore)
    Sporangium type
    the spores are enclosed in a hardened, capsule-like structure (sporocarp)
    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)

In New England

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.

Connecticut
extremely rare (S-rank: S1), endangered (code: E)
Maine
extremely rare (S-rank: S1), special concern (code: SC)
Massachusetts
rare (S-rank: S2), threatened (code: T)
New Hampshire
extremely rare (S-rank: S1), endangered (code: E)
Rhode Island
extremely rare (S-rank: S1), state endangered (code: SE)
Vermont
extremely rare (S-rank: S1)

From Flora Novae Angliae dichotomous key

1.  Ophioglossum pusillum Raf. NC

northern adder’s-tongue fern. Ophioglossum vulgatum L. var. pseudopodum (Blake) Farw. 
• CT, MA, ME, NH, RI, VT. Wet-mesic to hydric open areas such as swales, meadows, boggy fields, and ditches, only rarely in shade.

Native to North America?

Yes

Sometimes confused with

Ophioglossum vulgatum:
trophophore blade ovate to trullate, somewhat shiny in life, firm-herbaceous, the base abruptly tapering, and plant usually found in partial or complete shade, such as swamps and floodplain forests (vs. O. pusillum, with the trophophore blade lanceolate or broad-lanceolate to elliptic or narrow-ovate, dull in life, herbaceous, the base usually gradually tapering, and plants usually found in the open, such as marshes, low fields, and ditches).
Platanthera clavellata:
leaf blade with parallel venation (vs. O. pusillum, with leaf blade with reticulate venation).

Synonyms

  • Ophioglossum vulgatum L. var. pseudopodum (Blake) Farw.

Family

Ophioglossaceae

Genus

Ophioglossum