Scirpus hattorianus — mosquito bulrush
![Inflorescences: Scirpus hattorianus. ~ By Arthur Haines. ~ Copyright © 2024 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-1000s1000/Cyperaceae/scirpus-hattorianus-in-ahaines.jpg)
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Facts
Mosquito bulrush is native to North America but was first described from plants that were introduced into Japan. It is often mistaken for its close relative dark-green bulrush (Scirpus atrovirens).
Habitat
Anthropogenic (man-made or disturbed habitats), marshes, meadows and fields, 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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enlargeCharacteristics
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Stem shape in cross-section
-
- the stem is roughly triangular in cross-section
- the stem is round or oval in cross-section
- Leaf blade width
- 5–9 mm
- Leaf blade 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 like a seed, and surrounded by scales
- Fruit length
- 0.7–1.1 mm
- Leaf position on plant
-
- some leaf attachment points are above the midpoint of the stem
- 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 triangular to terete (circular) in cross-section
-
Flowers
- 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
- 1–2 mm
- Floral scale nerves
- 1
- Floral scale shape
- the floral scales are elliptic (widest in the middle and tapering toward each end)
- Floral scale translucent
- the floral scales are opaque
- Inflorescence bract angle
- the bracts are angled outwards near horizontal or reflexed downwards
- 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 crowded together in one tight cluster
- 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
- there are bristles attached at the base of the achene
- Stamen number
-
- 1
- 2
- 3
- Stigma number
- 3
- Style division
- the top two thirds of the style is divided
- floral bristle barbs
- the bristles have tiny barbs on them
-
Fruits or seeds
- 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
- 0.7–1.1 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
- 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
- 200–350 mm
- Leaf blade width
- 5–9 mm
- Leaf form
- all the leaves hold their form out of water
- Leaf position on plant
-
- some leaf attachment points are above the midpoint of the stem
- 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
-
Place
- Habitat
-
- terrestrial
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- edges of wetlands
- man-made or disturbed habitats
- marshes
- meadows or fields
-
Stem, shoot, branch
- Plant height
- Up to 150 cm
- Stem shape in cross-section
-
- the stem is roughly triangular 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
- 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
7. Scirpus hattorianus Makino N
mosquito bulrush. CT, MA, ME, NH, RI, VT. Wet fields, graminoid marshes, ditches, open, seasonally wet areas.
2×7. Scirpus atrocinctus × Scirpus hattorianus → Scirpus ×peckii Britt. is an uncommon bulrush nothospecies that is known from CT, MA, ME, NH, RI, VT. It has individual spikelets that somewhat resemble those of S. atrocinctus; however, the clusters of spikelets are borne on relatively stiff, straight inflorescence branches. The perianth bristles are elongate and somewhat bent but have a few remote barbules along their length. This hybrid appears to be much less frequent in the southern New England states.
Native to North America?
Yes
Sometimes confused with
- Scirpus atrovirens:
- fruits 1.1-1.3 mm long with perianth bristles longer than the fruits (vs. S. hattorianus, with fruits 0.8-1.1 mm long, with perianth bristles that are shorter than to as long as the fruit).