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Malaxis unifolia — green adder's-mouth

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Facts

Green adder's-mouth is a very small orchid with tiny, green flowers and a single leaf. Darwin noted in 1877 that in this genus (Malaxis) the flowers "though so small and inconspicuous, are highly attractive to insects…[as] shown by the pollinia [pollen sacs] having been removed from all the flowers on the spike." It is pollinated by small flies.

Habitat

Anthropogenic (man-made or disturbed habitats), swamps, 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 arrangement
alternate: there is one leaf per node along the stem
Number of leaves on stem
  • one
  • two
Form of lower petal
the labellum does not have a pouch-like shape
Lower petal outline
the labellum is lobed but not fringed
Main color of lower petal
  • blue to purple
  • green to brown
  • yellow
Nectar spur
there are no nectar spurs on the flower
Inflorescence type
the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
Lower petal characteristics
the labellum is lobed
Lower petal length
1.1–2.3 mm
Sepal length
1.1–2.2 mm
Show all characteristics

  • Flowers

    Flower bract length
    0.16–1.4 mm
    Flower petal color
    • green
    • yellow
    Flower symmetry
    there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
    Flowering date
    • August
    • July
    • June
    • September
    Flowers per inflorescence
    10–160
    Form of lower petal
    the labellum does not have a pouch-like shape
    Hairs on flower stalk
    the flower stalk has no hairs on it
    Hairs on inflorescence axis
    the main stem of the inflorescence is hairless
    Inflorescence length
    10–130 mm
    Inflorescence type
    the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
    Labellum position
    the labellum is in the lower position on the flower
    Length of flower stalk
    3.8–13 mm
    Length of narrowed base of lower petal
    0 mm
    Lobes at base of lower petal
    0.4–1.1 mm
    Lower petal characteristics
    the labellum is lobed
    Lower petal length
    1.1–2.3 mm
    Lower petal outline
    the labellum is lobed but not fringed
    Lower petal strongly red-veined
    no
    Main color of lower petal
    • blue to purple
    • green to brown
    • yellow
    Nectar spur
    there are no nectar spurs on the flower
    Nectar spur length
    0 mm
    Number of stamens
    1
    Orientation of side petals
    the lateral petals slant somewhat downward
    Pollen sacs
    the pollinia remain intact and do not fragment into smaller parts
    Self-pollinating flowers
    there are no cleistogamous flowers on this plant
    Sepal length
    1.1–2.2 mm
    Sepals fused only to sepals
    the sepals are separate from one another
    Spots on lower petal
    no
    Spur opening membrane
    NA
    Spur opening shape
    NA

  • Fruits or seeds

    Seed capsule orientation
    • the capsule bends downwards or hangs downwards
    • the capsule points upwards or is angled outwards

  • Growth form

    Plant green or not
    the plant is chlorophyllous (it has green parts)
    Roots
    the rhizomes do not resemble coral
    Underground organs
    • the plant has one or more swollen storage organs underground, such as bulbs, tubers or corms
    • there are only slender roots on the plant

  • Leaves

    Bract relative length
    the bract is shorter than the associated flower
    Features of leaves
    the leaf does not have any of the mentioned special features
    Leaf arrangement
    alternate: there is one leaf per node along the stem
    Leaf blade edges
    the edges of the leaf blade have no teeth
    Leaf blade length
    16–100 mm
    Leaf blade length to width ratio
    2–3
    Leaf blade shape
    the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    Leaf blade tip
    the tip of the leaf blade is acute (sharply pointed)
    Leaf blade width
    5–50 mm
    Leaves during flowering
    there are leaves on the plant when it is flowering
    Number of leaves on stem
    • one
    • two

  • 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
    • swamps

Wetland status

Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)

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)
Massachusetts
rare (uncertain) (S-rank: S2?)
New Hampshire
rare (S-rank: S2), threatened (code: T)
Rhode Island
extremely rare (S-rank: S1), state endangered (code: SE)
Vermont
rare (S-rank: S2)

From Flora Novae Angliae dichotomous key

3.  Malaxis unifolia Michx. N

green adder’s-mouth. Microstylis unifolia (Michx.) B.S.P. • CT, MA, ME, NH, RI, VT. Swamps, wetland borders, forest cuts and openings, cleared rights-of-way.

Native to North America?

Yes

Sometimes confused with

Malaxis bayardii:
basal auricles of labellum 0.8–1.1 mm long, 0.6 or more times as long as labellum, and pedicels mostly 3.4–5 mm long (vs. M. unifolia, with basal auricles of labellum 0.4–1.1 mm long, less than 0.6 times as long as labellum, and pedicels mostly 5–10 mm long).

Synonyms

  • Microstylis unifolia (Michx.) B.S.P.

Family

Orchidaceae

Genus

Malaxis