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- Dichotomous Key
- Cyperaceae
- Schoenoplectus
- Schoenoplectus subterminalis
Schoenoplectus subterminalis — water bulrush
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Facts
Water bulrush has disjunct eastern and western populations in North America. It often forms lawnlike mats underwater in lakes and slow-moving rivers.
Habitat
Lacustrine (in lakes or ponds), riverine (in rivers or streams)
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
- aquatic
- 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
- 0.2–1 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 appears to come from the side of the plant because the involucral bract at its base looks like an extension of the main stem
- Inflorescence branching
- the inflorescence is on one or more stems with no branches
- Fruit type (general)
- the fruit is like a seed, and surrounded by scales
- Fruit length
- 2.5–3.5 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 triangular to terete (circular) in cross-section
-
Flowers
- Anther length
- 2–3.5 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
- 4–6 mm
- Floral scale shape
-
- the floral scales are lanceolate (widest below the middle, and tapering at both ends)
- the floral scales are ovate (roughly egg-shaped)
- Floral scale translucent
- the floral scales are translucent
- Flower number per cluster
- 1
- Inflorescence bract angle
- the bracts are vertical or angled only slightly outwards
- Inflorescence bract number
- 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 on one or more stems with no branches
- Inflorescence crowding
-
- NA
- the inflorescence is crowded together in one tight cluster
- 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
- 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
- there are bristles attached at the base of the achene
- Stamen number
- 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
- plantlets budding at flower bases
- no
-
Fruits or seeds
- Achene beak length
- 0.3–0.8 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 triangular to terete (circular) in cross-section
- Fruit length
- 2.5–3.5 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
- 1 mm
- Underground organs
-
- the plant has a rhizome (a horizontal underground stem with roots growing from it)
- the plant has one or more swollen storage organs underground, such as bulbs or tubers
-
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 elliptic or circular in cross-section
- the leaf blade is flat or rolled in at the edges
- Leaf blade length
- Up to 50 mm
- Leaf blade width
- 0.2–1 mm
- Leaf form
- the leaves are extremely fine, or they are floating leaves, and do not 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
- there are no leaves on the main stem, or there is a small tooth or tiny blade, or a leaf sheath with no blade
- Width of seed-producing inflorescence
- 4–7 mm
-
Place
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- in lakes or ponds
- in rivers or streams
-
Stem, shoot, branch
- Plant height
- 20–150 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
- 0.5–1 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.
- Rhode Island
- extremely rare (S-rank: S1), state threatened (code: ST)
- Vermont
- uncommon (uncertain) (S-rank: S3?)
From Flora Novae Angliae dichotomous key
9. Schoenoplectus subterminalis (Torr.) Soják N
water bulrush. Scirpus subterminalis Torr. • CT, MA, ME, NH, RI, VT. Shallow water of lakes and slow-moving rivers, often forming large mats of thin, flaccid, narrow leaves underwater.