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Schoenoplectus etuberculatus — Canby's bulrush

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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

Canby's bulrush, a wetland plant of the coastal plain, enters New England only via a single population, located in southern Rhode Island. This is unusual because it is more than two hundred and fifty miles from the next population in Delaware. It occurs on pond shores and marshes along the coastal plain.

Habitat

Brackish or salt marshes and flats, fresh tidal marshes or flats, marshes, shores of rivers or lakes

Characteristics

Habitat
  • aquatic
  • wetlands
New England state
Rhode Island
Stem shape in cross-section
the stem is roughly triangular in cross-section
Leaf blade width
2–10 mm
Leaf blade cross-section
  • the leaf blade is flat or rolled in at the edges
  • the leaf blade is triangular in cross-section
Inflorescence position
the inflorescence appears to come from the side of the plant because the involucral bract at its base looks like an extension of the main stem
Inflorescence branching
the inflorescence is branched
Fruit type (general)
the fruit is like a seed, and surrounded by scales
Fruit length
3–4.5 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
Fruit cross-section
the fruit is triangular to terete (circular) in cross-section
Show all characteristics
  • Flowers

    Anther length
    3–3.5 mm
    Floral bristle color
    the bristles are slightly or strongly colored with reddish brown
    Floral bristle number
    5-7
    Floral bristle relative length
    the bristles are between one tenth as long as the achene, and equal in length to the achene
    Floral bristles
    the bristles are straight or slightly curved
    Floral scale hairs
    the floral scales have hairs on them
    Floral scale length
    5–7 mm
    Floral scale nerves
    • 2-5
    • 7 or more
    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
    Inflorescence bract angle
    the bracts are vertical or angled only slightly outwards
    Inflorescence bract number
    there are two to five bracts per 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 branched
    Inflorescence crowding
    the inflorescence is at least somewhat spread out, with at least one branch coming from the main stem
    Inflorescence position
    the inflorescence appears to come from the side of the plant because the involucral bract at its base looks like an extension of the main stem
    Inflorescence shape
    the aggregations within the inflorescence are roughly circular (not flattened) in cross-section
    Inflorescence type
    there are two or more flowers, spikes or flower clusters on a branched inflorescence
    Perianth composition
    there are bristles 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 have tiny barbs on them
    plantlets budding at flower bases
    no
  • Fruits or seeds

    Achene beak length
    0.7–2 mm
    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 triangular to terete (circular) in cross-section
    Fruit length
    3–4.5 mm
    Fruit type (general)
    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
    Rhizome thickness
    1–3 mm
    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
    • the leaf blade is triangular in cross-section
    Leaf blade length
    Up to 80 mm
    Leaf blade width
    2–10 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 fully-developed leaves with leaf blades on the main stem
    • there are no leaves on the main stem, or there is a small tooth or tiny blade, or a leaf sheath with no blade
  • Place

    Habitat
    • aquatic
    • wetlands
    New England state
    Rhode Island
    Specific habitat
    • brackish or salt marshes and flats
    • fresh tidal marshes or flats
    • marshes
    • shores of rivers or lakes
  • Stem, shoot, branch

    Plant height
    60–200 cm
    Stem shape in cross-section
    the stem is roughly triangular in cross-section
    Stem texture near tip
    the stem feels smooth near the tip
    Stem thickness at midpoint
    1–10 mm

Wetland status

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

New England distribution and conservation status

Distribution

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

Conservation status

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

Rhode Island
extremely rare (S-rank: S1), state endangered (code: SE)

Native to North America?

Yes

Sometimes confused with

Schoenoplectus torreyi

Family

Cyperaceae

From the dichotomous key of Flora Novae Angliae

3.  Schoenoplectus etuberculatus (Steud.) Soják NC

Canby’s bulrush. Scirpus etuberculatus (Steud.) Kuntze • RI. Pond shores and fresh to brackish marshes along the coastal plain.