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Schoenoplectus tabernaemontani — soft-stemmed bulrush

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Facts

Soft-stemmed bulrush has a nearly worldwide distribution and is found throughout North America and New England. It occurs in lake and river shores, marshes and ditches. As the name suggests, the stems have relatively large air cavities, which make it compress easily when squeezed.

Habitat

Anthropogenic (man-made or disturbed habitats), brackish or salt marshes and flats, floodplain (river or stream floodplains), fresh tidal marshes or flats, marshes, 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
  • terrestrial
  • 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
1–4 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
Fruit type (general)
the fruit is like a seed, and surrounded by scales
Fruit length
1.7–2.3 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 lenticular (lens-shaped) in cross-section
Show all characteristics

  • Flowers

    Anther length
    1.5–2 mm
    Floral bristle color
    the bristles are pale brown to 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
    there are no hairs on the floral scales
    Floral scale length
    2–3.5 mm
    Floral scale nerves
    0
    Floral scale shape
    the floral scales are ovate (roughly egg-shaped)
    Floral scale translucent
    the floral scales are opaque
    Flower number per cluster
    • 5-20
    • more than 20
    Inflorescence bract angle
    the bracts are vertical or angled only slightly outwards
    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 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
    • 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 are bristles attached at the base of the achene
    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 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
    1.7–2.3 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
    3–10 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
    Leaf blade length
    2–200 mm
    Leaf blade width
    1–4 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
    • aquatic
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • brackish or salt marshes and flats
    • edges of wetlands
    • fresh tidal marshes or flats
    • man-made or disturbed habitats
    • marshes
    • river or stream floodplains
    • shores of rivers or lakes

  • Stem, shoot, branch

    Plant height
    50–300 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
    2–10 mm

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.

Massachusetts
unranked (S-rank: SNR)

From Flora Novae Angliae dichotomous key

10.  Schoenoplectus tabernaemontani (K.C. Gmel.) Palla N

soft-stemmed bulrush. Schoenoplectus validus (Vahl) A. & D. Löve; Scirpus lacustris L. ssp. creber (Fern.) T. Koyama; S. tabernaemontani K.C. Gmel.; S. validus Vahl; S. validus Vahl 
var. creber Fern. • CT, MA, ME, NH, RI, VT. Lake shores, river shores, marshes, fresh to brackish-tidal marshes, ditches.

1×10. Schoenoplectus acutus × Schoenoplectus tabernaemontani → This uncommon bulrush hybrid is to be expected anywhere both parents 
are found growing together. Utilizing only reproductive characters, one can find it difficult to distinguish this hybrid without extreme familiarity with the parental taxa. However, the two species are very different in their vegetative anatomy. The hybrid 
has 5–8 aerenchymal lacunae in cross-section at ⅔ stem height, each airspace 
mostly 0.6–1.5 mm in diameter (see identification key for parental character states).

5×10. Schoenoplectus heterochaetus × Schoenoplectus tabernaemontani → Schoenoplectus ×‌steinmetzii (Fern.) S.G. Sm. is a very rare bulrush 
hybrid in New England. It shows a high proportion of solitary spikelets (similar to 
 S. heterochaetus); however, the achenes are weakly trigonous in cross-section and 
have usually 4 or 5 perianth bristles. Also, the stems have 5–7 aerenchymal lacunae 
in cross-section at ⅔ stem height that are mostly 0.7–1.4 mm in diameter. This 
hybrid is known only from ME within New England (it is still extant at the type locality).

Native to North America?

Yes

Sometimes confused with

Schoenoplectus acutus:
stems firm with many tiny air spaces and spikelets in clusters of 3-7 (vs. S. tabernaemontani, with stems soft with few large air spaces and spikelets solitary or in clusters of 2 or 3).

Synonyms

  • Schoenoplectus validus (Vahl) A. & D. Löve
  • Scirpus lacustris L. ssp. creber (Fern.) T. Koyama
  • Scirpus tabernaemontani K.C. Gmel.
  • Scirpus validus Vahl
  • Scirpus validus Vahl var. creber Fern.

Family

Cyperaceae

Genus

Schoenoplectus