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Triglochin palustre — marsh arrow-grass

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Facts

Marsh arrow-grass, found not only in salt marshes, but also ice-scoured river shores, has a split New England distribution in Maine and Rhode Island. Its distribution across northern North America and the mountainous West is similarly characterized by scattered isolated occurrences. It is also found in Eurasia. The bulbs are a primary protein source for greater white-fronted geese (Anser albifrons frontalis) in Alaska.

Habitat

Brackish or salt marshes and flats, floodplain (river or stream floodplains), marshes, intertidal, subtidal or open ocean, 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
  • Maine
  • Rhode Island
Stem shape in cross-section
the stem is round or oval in cross-section
Leaf blade width
0.8–1.4 mm
Leaf blade cross-section
the leaf blade is elliptic or circular in cross-section
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 a capsule, with at least three seeds in it
Fruit length
7–8.3 mm
Leaf position on plant
the attachment points of all the leaves are at or near the base of the plant
Perianth composition
the perianth is green or brown, with six sepal-like parts, and a leafy texture
Fruit cross-section
the fruit is triangular to terete (circular) in cross-section
Show all characteristics

  • Flowers

    Floral bristle color
    NA
    Floral bristle number
    NA
    Floral bristle relative length
    NA
    Floral bristles
    NA
    Floral scale hairs
    NA
    Floral scale length
    0 mm
    Floral scale nerves
    NA
    Inflorescence bract angle
    NA
    Inflorescence bract number
    NA
    Inflorescence bract position (Sparganium)
    NA
    Inflorescence bracts
    NA
    Inflorescence branching
    the inflorescence is on one or more stems with no branches
    Inflorescence crowding
    the inflorescence is at least somewhat spread out, with at least one branch coming from the main stem
    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
    the perianth is green or brown, with six sepal-like parts, and a leafy texture
    Stamen number
    4-6
    Stigma number
    3
    Style division
    NA
    floral bristle barbs
    NA

  • Fruits or seeds

    Achene beak length
    0 mm
    Achene surface texture
    NA
    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
    7–8.3 mm
    Fruit type (general)
    the fruit is a capsule, with at least three seeds in it
    Fruit type (specific)
    • the fruit is a non-wind-dispersed follicle (has one ovary that splits along one side to release the seeds)
    • the fruit is a schizocarp (when dry it splits into sections, each holding one or more seeds)
    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 texture
    the auricles are weak, papery and translucent
    Auricles
    the leaf sheath has auricles on it
    Leaf blade cross-section
    the leaf blade is elliptic or circular in cross-section
    Leaf blade length
    60–245 mm
    Leaf blade width
    0.8–1.4 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 fully-developed leaves with leaf blades on the main stem
    Width of seed-producing inflorescence
    2–5 mm

  • Place

    Habitat
    • aquatic
    • wetlands
    New England state
    • Maine
    • Rhode Island
    Specific habitat
    • brackish or salt marshes and flats
    • intertidal, subtidal or open ocean
    • marshes
    • river or stream floodplains
    • shores of rivers or lakes

  • Stem, shoot, branch

    Plant height
    9–42.5 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
absent
Maine
present
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
historical (S-rank: SH), state historical (code: SH)

From Flora Novae Angliae dichotomous key

3.  Triglochin palustre L. N

marsh arrow-grass. ME, RI; also reported from NH by Haynes and Hellquist (2000b), but specimens are unknown. Saline marshes, ice-scoured river shores.

Native to North America?

Yes

Sometimes confused with

Triglochin maritima:
mature fruits mostly 2 times as long as wide, with 6 stigmas (vs. T. palustre, with mature fruits mostly 5-7 times as long as wide, with 3 stigmas).

Family

Juncaginaceae

Genus

Triglochin