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Trichophorum alpinum — alpine bulrush, alpine clubsedge

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Facts

Alpine clubsedge is a circumboreal species native across Canada and some northern states of the United States. It inhabits fens, streamsides and meadows, often in lime-rich situations. The mature perianth bristles look from a distance like freshly-fallen snow.

Habitat

Fens, meadows and fields, shores of rivers or lakes

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
  • aquatic
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Stem shape in cross-section
the stem is roughly triangular in cross-section
Leaf blade width
0.4–0.5 mm
Leaf blade cross-section
the leaf blade is flat or rolled in at the edges
Inflorescence position
the inflorescence is at the tip of the plant
Inflorescence branching
the inflorescence is on one or more stems with no branches
Fruit type (general)
  • the fruit is like a seed, and surrounded by hairs
  • the fruit is like a seed, and surrounded by scales
Fruit length
1.2–1.6 mm
Leaf position on plant
the attachment points of all the leaves are at or near the base of the plant
Perianth composition
  • there are bristles attached at the base of the achene
  • there are long, thin hairs attached at the base of the achene
Fruit cross-section
the fruit is lenticular (lens-shaped) in cross-section
Show all characteristics
  • Flowers

    Anther length
    1.1–1.6 mm
    Floral bristle color
    the bristles are white
    Floral bristle number
    5-7
    Floral bristle relative length
    the bristles are longer than the achene
    Floral bristles
    the bristles are straight or slightly curved
    Floral scale hairs
    there are no hairs on the floral scales
    Floral scale shape
    • the floral scales are lanceolate (widest below the middle, and tapering at both ends)
    • the floral scales are ovate (roughly egg-shaped)
    Floral scale translucent
    the floral scales are opaque
    Flower number per cluster
    5-20
    Inflorescence bract angle
    the bracts are vertical or angled only slightly outwards
    Inflorescence bract number
    there is just one bract on the inflorescence
    Inflorescence bract position (Sparganium)
    NA
    Inflorescence bracts
    there is only one bract, and it looks like a continuation of the stem
    Inflorescence branching
    the inflorescence is on one or more stems with no branches
    Inflorescence crowding
    NA
    Inflorescence position
    the inflorescence is at the tip of the plant
    Inflorescence shape
    the aggregations within the inflorescence are roughly circular (not flattened) in cross-section
    Inflorescence type
    there is one spike or raceme at the tip of the stem
    Perianth composition
    • there are bristles attached at the base of the achene
    • there are long, thin hairs attached at the base of the achene
    Stamen number
    3
    Stigma number
    3
    Style division
    the top two thirds of the style is divided
    floral bristle barbs
    the bristles do not have barbs on them
  • Fruits or seeds

    Achene surface texture
    the achene is smooth (it has no detectable texture)
    Achene tubercle relative width
    NA
    Achene tubercle width
    0 mm
    Capsule relative length
    NA
    Fruit cross-section
    the fruit is lenticular (lens-shaped) in cross-section
    Fruit length
    1.2–1.6 mm
    Fruit type (general)
    • the fruit is like a seed, and surrounded by hairs
    • the fruit is like a seed, and surrounded by scales
    Fruit type (specific)
    the fruit is an achene (dry, seed-like fruit) without a tubercle (a swelling or projection, usually of a different color or texture)
    Locules in capsule
    NA
    Seed length
    0 mm
    Seed tail relative length
    0 mm
    Seed tails
    NA
    Tubercle height
    0 mm
  • Growth form

    Lifespan
    the plant lives more than two years
    Underground organs
    the plant has a rhizome (a horizontal underground stem with roots growing from it)
  • Leaves

    Auricle length
    0 mm
    Auricle texture
    NA
    Auricles
    there are no auricles on the leaf sheath
    Leaf blade cross-section
    the leaf blade is flat or rolled in at the edges
    Leaf blade length
    6–9 mm
    Leaf blade width
    0.4–0.5 mm
    Leaf form
    all the leaves hold their form out of water
    Leaf position on plant
    the attachment points of all the leaves are at or near the base of the plant
    Leaf septa
    the leaf blades do not have transverse septa
    Leaf sheath hairs
    the leaf sheathes are without hairs
    Pedicel length (Typha)
    0 mm
    Stem leaf blade ligules
    the plant has ligules at the leaf blade bases
    Stem leaf blades
    there are no leaves on the main stem, or there is a small tooth or tiny blade, or a leaf sheath with no blade
    Width of seed-producing inflorescence
    2.2–3.5 mm
  • Place

    Habitat
    • aquatic
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • fens
    • meadows or fields
    • shores of rivers or lakes
  • Stem, shoot, branch

    Plant height
    10–40 cm
    Stem shape in cross-section
    the stem is roughly triangular in cross-section
    Stem texture near tip
    the edges of the stem feel rough near the tip

Wetland status

Occurs only in wetlands. (Wetland indicator code: OBL)

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
historical (S-rank: SH), special concern, extirpated (code: SC*)
Maine
unranked (S-rank: SNR)
Massachusetts
fairly widespread (S-rank: S4)
Rhode Island
historical (S-rank: SH), state historical (code: SH)

From Flora Novae Angliae dichotomous key

1.  Trichophorum alpinum (L.) Pers. N

alpine clubsedge. Baeothryon alpinum (L.) Egor.; Eriophorella alpina (L.) Holub; Eriophorum alpinum L.; Scirpus hudsonianus (Michx.) Fern. • CT, MA, ME, NH, RI, VT. Fens, wet rocks, stream shores, circumneutral meadows.

Native to North America?

Yes

Sometimes confused with

Eriophorum vaginatum:
perianth bristles numbering 10–25 per flower and spikelets 10–50 mm long in fruit, subtended by 10–15 sterile, basal scales (vs. T. alpinum, with perianth bristles mostly 6 in each flower and spikelets 5.4–8 mm tall in fruit, subtended by a solitary involucral bract that resembles an enlarged, basal scale).

Synonyms

  • Baeothryon alpinum (L.) Egor.
  • Eriophorella alpina (L.) Holub
  • Eriophorum alpinum L.
  • Scirpus hudsonianus (Michx.) Fern.

Family

Cyperaceae

Genus

Trichophorum