Schoenoplectus purshianus (Fern.) M.T. Strong

weak-stalked 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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At Concord

The variety in Concord is var. purshianus.

Facts About

Weak-stalked bulrush inhabits pond shores and temporary pools in all New England states. There are two varieties, one of which is common and widespread (Schoenoplectus purshianus var. purshianus), the other (S. purshianus var. williamsii) being known from only a single population in Massachusetts.

Habitat

Shores of rivers or lakes, wetland margins (edges of wetlands)

Characteristics

Habitat
wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Stem shape in cross-section
the stem is round or oval in cross-section
Leaf blade width
0.5–1 mm
Leaf blade cross-section
  • NA
  • the leaf blade is flat or rolled in at the edges
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
  • the inflorescence is at the tip of the plant
Inflorescence branching
the inflorescence is branched
Fruit type (general)
the fruit is like a seed, and surrounded by scales
Fruit length
1.75–2 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 is no perianth on the plant
Fruit cross-section
the fruit is biconvex or elliptic (widest in the middle and tapering to both ends) in cross-section
Show All Characteristics
  • Flowers
    Anther length
    0.4–0.6 mm
    Floral bristle color
    the bristles are pale brown to brown
    Floral bristle number
    • 0
    • 5-7
    Floral bristle relative length
    • the bristles are between one tenth as long as the achene, and equal in length to the achene
    • the bristles are longer than the achene
    Floral bristles
    the bristles are straight or slightly curved
    Floral scale hairs
    the floral scales have hairs on them
    Floral scale length
    2.5–3 mm
    Floral scale nerves
    • 2-5
    • 7 or more
    Floral scale shape
    the floral scales are obovate (roughly egg-shaped, but with the widest part above the middle)
    Floral scale translucent
    the floral scales are opaque
    Inflorescence bract angle
    the bracts are angled outwards near horizontal or reflexed downwards
    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 branched
    Inflorescence crowding
    • NA
    • the inflorescence is crowded together in one tight cluster
    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
    • 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 are two or more flowers, spikes or flower clusters on a branched inflorescence
    • 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 is no perianth on the plant
    Stamen number
    3
    Stigma number
    • 2
    • 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
    0.1–0.3 mm
    Achene surface texture
    the achene has very obvious pits or depressions on it
    Achene tubercle relative width
    NA
    Achene tubercle width
    0 mm
    Capsule relative length
    NA
    Fruit cross-section
    the fruit is biconvex or elliptic (widest in the middle and tapering to both ends) in cross-section
    Fruit length
    1.75–2 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 only a single year or less
    Rhizome thickness
    1 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
    • NA
    • the leaf blade is flat or rolled in at the edges
    Leaf blade width
    0.5–1 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
  • Place
    Habitat
    wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • edges of wetlands
    • shores of rivers or lakes
  • Stem, shoot, branch
    Plant height
    10–100 cm
    Stem shape in cross-section
    the stem is round or oval in cross-section
    Stem texture near tip
    the stem feels smooth near the tip
    Stem thickness at midpoint
    0.5–1 mm

Wetland Status

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

New England Distribution and Conservation Status

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.

Vermont
uncommon (S-rank: S3)

Native to North America?

Yes

Family

Cyperaceae

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