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Lipocarpha micrantha — small-flowered dwarf-bulrush

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Facts

Small-flowered dwarf-bulrush inhabits sandy shores of lakes, ponds, and sometimes tidal rivers. "Dwarf" and "small" are apt names for this tiny plant, which only grows to 6 inches (15 cm) tall at most, with thread-like, drooping leaves. The fruiting head appears to emerge from the side of the stem because it is overtopped by a small bract. The species is regarded as very rare in all five of the New England states in which it occurs, as well as in many other states. Its sandy shore habitat is threatened by recreation and trampling.

Habitat

Brackish or salt marshes and flats, floodplain (river or stream floodplains), fresh tidal marshes or flats, shores of rivers or lakes, 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
  • aquatic
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
Stem shape in cross-section
the stem is round or oval in cross-section
Leaf blade width
0.3–0.5 mm
Leaf blade cross-section
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
  • the inflorescence is on one or more stems with no branches
Fruit type (general)
the fruit is like a seed, and surrounded by scales
Fruit length
0.5–0.7 mm
Leaf position on plant
the attachment points of all the leaves are at or near the base of the plant
Perianth composition
there is a single, small scale 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
    0.1–0.2 mm
    Floral bristle color
    NA
    Floral bristle number
    0
    Floral bristle relative length
    NA
    Floral bristles
    NA
    Floral scale hairs
    there are no hairs on the floral scales
    Floral scale length
    0.1–1 mm
    Floral scale nerves
    1
    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
    Flower number per cluster
    • 5-20
    • more than 20
    Inflorescence bract angle
    the bracts are angled outwards near horizontal or reflexed downwards
    Inflorescence bract number
    • there are two to five bracts per inflorescence
    • there is just one bract on the inflorescence
    Inflorescence bract position (Sparganium)
    NA
    Inflorescence bracts
    there are at least two bracts, and they are either flat or folded or rolled in at the edges
    Inflorescence branching
    • the inflorescence is branched
    • the inflorescence is on one or more stems with no branches
    Inflorescence crowding
    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
    Perianth composition
    there is a single, small scale at the base of the achene
    Stamen number
    1
    Stigma number
    2
    Style division
    the style is divided nearly from the base
    floral bristle barbs
    NA
    plantlets budding at flower bases
    no

  • Fruits or seeds

    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 triangular to terete (circular) in cross-section
    Fruit length
    0.5–0.7 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
    Underground organs
    there are only slender roots on the plant

  • 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
    15–100 mm
    Leaf blade width
    0.3–0.5 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
    there are no ligules at the leaf blade bases
    Stem leaf blades
    there are fully-developed leaves with leaf blades on the main stem
    Width of seed-producing inflorescence
    1–2 mm

  • Place

    Habitat
    • aquatic
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    Specific habitat
    • brackish or salt marshes and flats
    • edges of wetlands
    • fresh tidal marshes or flats
    • river or stream floodplains
    • shores of rivers or lakes

  • Stem, shoot, branch

    Plant height
    2–20 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

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
absent

Conservation status

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

Connecticut
extremely rare (S-rank: S1), threatened (code: T)
Maine
extremely rare (S-rank: S1), threatened (code: T)
Massachusetts
rare (S-rank: S2), threatened (code: T)
New Hampshire
historical (S-rank: SH), endangered (code: E)
Rhode Island
extremely rare (S-rank: S1), state threatened (code: ST)

From Flora Novae Angliae dichotomous key

1.  Lipocarpha micrantha (Vahl) G. Tucker N

small-flowered dwarf-bulrush. Hemicarpha micrantha (Vahl) Pax; Scirpus micranthus Vahl • CT, MA, ME, NH, RI. Sandy shorelines, usually of lakes and ponds, rarey on fresh-tidal river shores.

Native to North America?

Yes

Family

Cyperaceae

Genus

Lipocarpha