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- Juncus dichotomus
Juncus dichotomus — forked rush
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Facts
Forked rush, native to the eastern and southern United States as well as New England, inhabits shorelines, ditches, coastal marsh edges in moist to wet sandy soil. It has been introduced in Europe and is considered invasive in some countries.
Habitat
Anthropogenic (man-made or disturbed habitats), marshes, shores of rivers or lakes, wetland margins (edges of wetlands)
New England distribution
Adapted from BONAP data
Native: indigenous.
Non-native: introduced (intentionally or unintentionally); has become naturalized.
County documented: documented to exist in the county by evidence (herbarium specimen, photograph). Also covers those considered historical (not seen in 20 years).
State documented: documented to exist in the state, but not documented to a county within the state. Also covers those considered historical (not seen in 20 years).
Note: when native and non-native populations both exist in a county, only native status is shown on the map.
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Characteristics
- Habitat
-
- terrestrial
- 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
- 0.5–1.2 mm
- Leaf blade cross-section
-
- the leaf blade is elliptic or circular in cross-section
- the leaf blade is flat or rolled in at the edges
- Inflorescence position
- the inflorescence is at the tip of the plant
- Inflorescence branching
- the inflorescence is branched
- Fruit type (general)
- the fruit is a capsule, with at least three seeds in it
- Fruit length
- 2.5–4.5 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
-
Flowers
- Anther color (dry)
- the anthers range in color from white to tan or yellow to yellow-brown
- Anther length
- 0.4–1 mm
- 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
- 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
- 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
- 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 are two or more flowers, spikes or flower clusters on a branched inflorescence
- Perianth composition
- the perianth is green or brown, with six sepal-like parts, and a leafy texture
- Stamen length
- 1–2.2 mm
- Stamen number
- 4-6
- Stigma number
- 3
- 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
-
- the capsule is about equal to the perianth
- the capsule is shorter than the perianth
- Fruit cross-section
- the fruit is triangular to terete (circular) in cross-section
- Fruit length
- 2.5–4.5 mm
- Fruit type (general)
- the fruit is a capsule, with at least three seeds in it
- 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)
- Locules in capsule
- the capsule has three locules
- Seed length
- 0.3–0.4 mm
- Seed tail relative length
- 0.3–0.4 mm
- Seed tails
- there is no tail on the seeds
- 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 length
- 0.2–0.6 mm
- Auricle texture
- the auricles are firm (though flexible) and opaque
- Auricles
- there are no auricles on the leaf sheath
- Leaf blade cross-section
-
- the leaf blade is elliptic or circular in cross-section
- the leaf blade is flat or rolled in at the edges
- Leaf blade length
- 100–400 mm
- Leaf blade width
- 0.5–1.2 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
-
Place
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Specific habitat
-
- edges of wetlands
- man-made or disturbed habitats
- marshes
- shores of rivers or lakes
-
Stem, shoot, branch
- Plant height
- 20–100 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
Wetland status
Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)
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.
- Massachusetts
- fairly widespread (S-rank: S4)
- New Hampshire
- historical (S-rank: SH), endangered (code: E)
From Flora Novae Angliae dichotomous key
16. Juncus dichotomus Ell. N
forked rush. Juncus platyphyllus (Wieg.) Fern.; J. tenuis Willd. var. dichotomus (Ell.) Wood • CT, MA, ME, NH, RI. Shorelines, ditches, upper border of coastal marshes, usually in mesic to hydric, sandy soil.
Native to North America?
Yes and no (some introduced)
Sometimes confused with
- Juncus dudleyi:
- leaves flat, though often involute in age or drying, inflorescence usually compact and few-flowered, often with 10 or fewer flowers, rarely more than 15 (vs. J. dichotomus, with leaves caniculate to nearly terete, rarely flat, and inflorescence varying from compact to open and diffuse, usually with 10–35 or more flowers).
- Juncus tenuis:
- auricles scarious, mostly 1.5–5 mm long, and sheath margin pliable, transparent (vs. J. dichotomus, with auricles scarious to cartilaginous, 0.2–0.6 mm long, and sheath margin of firmer texture, often brittle, nearly opaque).
Synonyms
- Juncus platyphyllus (Wieg.) Fern.
- Juncus tenuis Willd. var. dichotomus (Ell.) Wood