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Native Plant Trust: Go Botany Discover thousands of New England plants

Glossostigma cleistanthum — mud-mat

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Facts

Mud-mat is aptly named: it is a small, mat-forming plant of mudflats and lakeshores, with upright, opposite leaves the length of your thumb. It is native to Australia and New Zealand. The species has been introduced in New England recently, and also shows up in various sites in the mid-Atlantic states, where it is thought to have escaped from aquarium culture, and where it is likely dispersed by Canada geese and other waterfowl. Although it is not a nuisance plant in its native range, the state of Washington has actually declared it a quarantined weed, just in case.

Habitat

Fresh tidal marshes or flats, 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
  • Connecticut
  • Massachusetts
  • Rhode Island
Flower petal color
white
Leaf type
the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
Leaf arrangement
opposite: there are two leaves per node along the stem
Leaf blade edges
the edge of the leaf blade is entire (has no teeth or lobes)
Flower symmetry
there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
Number of sepals, petals or tepals
there are five petals, sepals, or tepals in the flower
Fusion of sepals and petals
the petals or the sepals are fused into a cup or tube
Stamen number
1 or 2
Fruit length
1.4–1.8 mm
Show all characteristics

  • Clonal plantlets

    Bulbils
    the plant does not appear to have bulbils
    Bulblets replace flowers
    there are no bulblets where the flowers are located

  • Flowers

    Carpels fused
    the carpels are fused to one another
    Corolla morphology
    the flower has two prominent lips
    Corolla palate
    no
    Corona lobe length
    0 mm
    Epicalyx
    the flower does not have an epicalyx
    Epicalyx number of parts
    0
    Flower description
    the flower has a superior ovary, and lacks a hypanthium
    Flower petal color
    white
    Flower reproductive parts
    the flower has both pollen- and seed-producing parts
    Flower symmetry
    there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
    Flowers sunken into stem
    no
    Form of style
    NA
    Fusion of sepals and petals
    the petals or the sepals are fused into a cup or tube
    Horns in hoods (Asclepias)
    NA
    Hypanthium
    the flower does not have a hypanthium
    Inflorescence one-sided
    the flowers are arrayed in a spiral around the inflorescence axis or branches, or occur singly, or in several ranks
    Inner tepals (Rumex)
    NA
    Nectar spur
    the flower has no nectar spurs
    Number of pistils
    1
    Number of sepals, petals or tepals
    there are five petals, sepals, or tepals in the flower
    Number of styles
    1
    Ovary position
    the ovary is above the point of petal and/or sepal attachment
    Petal and sepal arrangement
    the flower includes two cycles of petal- or sepal-like structures
    Petal and sepal colors
    white
    Petal appearance
    the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal folds or pleats
    the petals of the flower do not have folds or plaits
    Petal hairs (Viola)
    NA
    Petal number
    5
    Petal tips (Cuscuta)
    NA
    Scales inside corolla
    no
    Sepal and petal color
    the sepals are different from the petals
    Sepal appendages
    the sepals do not have appendages on them
    Sepal appendages (Oenothera)
    NA
    Sepal length
    1.5–3 mm
    Sepal number
    5
    Sepals fused only to sepals
    the sepals are fused to each other (not other flower parts), at least near their bases
    Stamen attachment
    the stamens are attached at or near the bases of the petals or tepals
    Stamen number
    1 or 2
    Stamen position relative to petals
    NA
    Stigma position
    the stigmas are positioned at the tip of the style
    Style petal-like
    the styles are not petal-like
    Umbel flower reproductive parts
    NA
    Upper lip of bilabiate corolla
    the upper lip of the bilabiate corolla has two lobes

  • Fruits or seeds

    Achene relative orientation
    NA
    Achene shape
    NA
    Achene surface (Polygonum)
    NA
    Achene type
    NA
    Berry color
    NA
    Capsule color (Viola)
    NA
    Capsule splitting
    the capsule splits by two main valves, teeth or pores
    Fruit (pyxis) dehiscence
    NA
    Fruit features (Brassicaceae)
    NA
    Fruit length
    1.4–1.8 mm
    Fruit locules
    two
    Fruit type (specific)
    the fruit is a capsule (splits along two or more seams, apical teeth or pores when dry, to release two or more seeds)
    Legumes (Fabaceae)
    NA
    Mericarp length
    0 mm
    Mericarp segment shape (Desmodium)
    NA
    Other markings on berry
    NA
    Ovary stipe
    the ovary or fruit does not have a stipe
    Placenta arrangement
    the plant has axile placentation, in which the ovules are attached where the septa of a compound ovary are united, usually on the central axis, or to the septa themselves
    Rows of seeds in fruit (Brassicaceae)
    NA
    Schizocarpic fruit compression
    NA
    Schizocarpic fruit segments
    0
    Septum in fruit (Brassicaceae)
    NA
    Wings on fruit
    the fruit does not have wings on it
    prickles on fruits
    the fruits do not have thorn-like defensive structures

  • Glands or sap

    Glands on leaf blade
    the leaf blades do not have glandular dots or scales
    Sap
    the sap is clear and watery
    Sap color
    the sap is clear

  • Growth form

    Growth form
    the plant is an herb (it has self-supporting stems)
    Lifespan
    • the plant lives more than two years
    • the plant lives only a single year or less
    Parasitism
    the plant is not parasitic
    Plant color
    the leaves or young stems of the plant are green
    Plants darken when dry
    no
    Spines on plant
    the plant has no spines
    Underground organs
    the plant has a rhizome (a horizontal underground stem with roots growing from it)

  • Leaves

    Bracteole number (Apiaceae)
    0
    Bracts in plantain (Plantago)
    NA
    Final leaf segment length (compound lvs only)
    0 mm
    Final leaf segment length to width ratio (compound lvs only)
    0
    Final leaf segment width (compound lvs only)
    0 mm
    Hairs on underside of leaf
    the underside of the leaf is not hairy, or it has very few hairs
    Hairs on upper side of leaf
    the upper side of the leaf is not hairy, or it has very few hairs
    Leaf arrangement
    opposite: there are two leaves per node along the stem
    Leaf blade base
    the leaf has no stalk
    Leaf blade base shape
    the base of the leaf blade is cuneate (wedge-shaped, tapers to the base with relatively straight, converging edges), or narrow
    Leaf blade edges
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf blade length
    4.5–57 mm
    Leaf blade shape
    the leaf blade is spatulate (spoon-shaped; narrow near the base, then suddenly widening to a rounded tip)
    Leaf blade surface colors
    the upper side of the leaf blade is relatively uniform in color
    Leaf blade width
    Up to 2 mm
    Leaf duration
    the leaves drop off in winter (or they whither but persist on the plant)
    Leaf form
    the leaves are green, with an expanded blade and a leaf-like texture
    Leaf spines
    there are no spines on the leaf edges
    Leaf stalk
    the leaves have no leaf stalks, but attach directly to the stem
    Leaf teeth and lobes
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf type
    the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Leaflet number
    0
    Leaves per node
    there are two leaves per node along the stem
    Pinnately compound leaf type
    NA
    Specific leaf type
    the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Stipels
    NA
    Stipule features
    NA
    Stipules
    there are no stipules on the plant

  • Place

    Habitat
    • aquatic
    • wetlands
    New England state
    • Connecticut
    • Massachusetts
    • Rhode Island
    Specific habitat
    • fresh tidal marshes or flats
    • shores of rivers or lakes

  • Stem, shoot, branch

    Branched tendrils
    NA
    Hair between stem nodes
    the stem has no hairs between the nodes
    Hairs between stem nodes
    the stem has no hairs between the nodes
    Leaves on stem
    there is at least one full leaf above the base of the flowering stem
    Plant height
    Up to 5.7 cm
    Stem orientation
    the stems trail at the base, but may turn upwards at the tips
    Tendril origin
    NA
    Tendrils
    the plant does not have tendrils

Wetland status

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

In New England

Distribution

Connecticut
present
Maine
absent
Massachusetts
present
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.

Massachusetts
not applicable (S-rank: SNA)

From Flora Novae Angliae dichotomous key

1.  Glossostigma cleistanthum W.R. Barker E

mud-mat. CT, MA, RI. Shallow water or wet silt and mud of lakes and rivers, including fresh-tidal reaches. Originally thought to be Glossostigma diandrum (L.) Kunze, New England collections of this species have been confirmed as G. cleistanthum through molecular analysis. This species shows longer leaves than G. diandrum (mostly longer than 10 mm vs. mostly shorter than 8 mm). This new arrival to New England is easily confused with Limosella australis. However, it has a pair of leaves at each node and flowers with 2 stamens (vs. a cluster of leaves at each node and flowers with 4 stamens in L. australis).

Native to North America?

No

Sometimes confused with

Limosella australis:
flowers with 4 stamens and each node of the stem with a cluster of leaves (vs. G. cleistanthum, with flowers with 2 stamens and each node of the stem with a pair of leaves).

Family

Phrymaceae

Genus

Glossostigma