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Corallorhiza odontorhiza — fall coral-root

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Facts

Although fall coral-root is uncommon to rare in New England, it is found in all states, although in Maine it is restricted to the southwest. This diminutive saprophyte lives off decayed organic matter and lacks fully-developed leaves.

Habitat

Forests

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
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Leaf arrangement
there are no apparent leaves except on the reproductive stems
Number of leaves on stem
NA
Form of lower petal
the labellum does not have a pouch-like shape
Lower petal outline
the labellum is simple in form
Main color of lower petal
white
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 simple in form
Lower petal length
2.7–4.6 mm
Sepal length
3–4.5 mm
Show all characteristics

  • Flowers

    Flower petal color
    • brown
    • green
    • purple
    • yellow
    Flower symmetry
    there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
    Flowering date
    • August
    • October
    • September
    Flowers per inflorescence
    5–26
    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
    30–60 mm
    Inflorescence type
    the inflorescence is a raceme (a long unbranched stem with stalked flowers growing along it)
    Inflorescence width
    10–25 mm
    Labellum position
    the labellum is in the lower position on the flower
    Lobes at base of lower petal
    0 mm
    Lower petal characteristics
    the labellum is simple in form
    Lower petal length
    2.7–4.6 mm
    Lower petal outline
    the labellum is simple in form
    Lower petal strongly red-veined
    no
    Main color of lower petal
    white
    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 are angled steeply upwards
    Self-pollinating flowers
    the plant has some cleistogamous flowers
    Sepal length
    3–4.5 mm
    Sepals fused only to sepals
    the sepals are separate from one another
    Spots on lower petal
    yes
    Spur opening membrane
    NA
    Spur opening shape
    NA

  • Fruits or seeds

    Fruit length
    5.5–8 mm
    Fruit width
    3.5–5 mm
    Seed capsule orientation
    the capsule bends downwards or hangs downwards

  • Growth form

    Plant green or not
    the plant is achlorophyllous (it has no green parts)
    Roots
    the rhizomes are branched and resemble coral
    Underground organs
    this plant has a rhizome (a horizontal underground stem with roots growing from it)

  • Leaves

    Bract relative length
    the bract is shorter than the associated flower
    Features of leaves
    • NA
    • the leaf does not have any of the mentioned special features
    Leaf arrangement
    there are no apparent leaves except on the reproductive stems
    Leaf blade edges
    NA
    Leaf blade length
    0 mm
    Leaf blade shape
    NA
    Leaf blade tip
    NA
    Leaf blade width
    0 mm
    Leaves during flowering
    NA
    Number of leaves on stem
    NA

  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    forests

Wetland status

Not classified

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
fairly widespread (S-rank: S4)
Maine
extremely rare (S-rank: S1), endangered (code: E)
New Hampshire
extremely rare (S-rank: S1), endangered (code: E)

var. odontorhiza

Massachusetts
uncommon (S-rank: S3), special concern (code: SC)
Rhode Island
extremely rare (S-rank: S1), state threatened (code: ST)
Vermont
rare (S-rank: S2), threatened (code: T)

From Flora Novae Angliae dichotomous key

2.  Corallorhiza odontorhiza (Willd.) Poir. NC

fall coral-root.  2b. Corallorhiza pringlei Greenman • CT, MA, ME, NH, RI, VT; scattered throughout New England but restricted in ME to the southwestern portion of the state. Dry-mesic to mesic, deciduous and evergreen-deciduous forests, usually with a relatively open understory, also often on sites influenced by circumneutral to basic bedrock.

1a.  Perianth often closed; stigmatic surface 0.3–0.5 mm wide; labellum 1.7–2.2 (–3) mm wide; column without or with poorly developed auricles at base on adaxial surface

… 2a. C. odontorhiza var. odontorhiza

1b.  Perianth open; stigmatic surface 0.7–1 mm wide; labellum 2–3.7 mm wide; column 
with 2 prominent auricles at base on adaxial surface 
 … 2b. C. odontorhiza var. pringlei (Greenman) Freudenstein

Variety odontorhiza is known from CT, MA, ME, NH, RI, VT. Variety pringlei is only known from 
CT and is of regional conservation concern; also reported from MA, ME, VT by Brown (1997), but specimens are unknown.

Native to North America?

Yes

Sometimes confused with

Corallorhiza maculata:
upper petals and sepals not closely positioned to form a galea-like structure, labellum with a lateral lobe or tooth on each side, and plants flowering in early July through late August or rarely into early September (vs. C. odontorhiza, with the upper petals and sepals +/- connivent to form a galea-like structure, labellum without lateral lobes, and plants mostly flowering in late August through late September).
Corallorhiza trifida:
upper petals and sepals not closely positioned to form a galea-like structure, labellum with a lateral lobe or tooth on each side, and plants flowering in mid-May through mid-June (vs. C. odontorhiza, with the upper petals and sepals +/- connivent to form a galea-like structure, labellum without lateral lobes, and plants mostly flowering in late August through late September).

Synonyms

  • Corallorhiza pringlei Greenman

Family

Orchidaceae

Genus

Corallorhiza