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- Water plants with leaves and stems
- Hypericum boreale
Hypericum boreale — northern St. John's-wort
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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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Facts
Northern St. John's-wort is native to Northeastern wetlands, and it is sometimes found in cranberry plantations. Its presence in cranberry farms in the Pacific Northwest, where it is not native, is thought to be due to inadvertent transfer with commercial cranberry plant cuttings.
Habitat
Lacustrine (in lakes or ponds), shores of rivers or lakes, swamps, wetland margins (edges of wetlands)
Characteristics
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf position
- the leaves are all submerged underwater
- Leaf arrangement
- opposite: there are two leaves per node along the stem
- Leaf blade length
- 6–34 mm
- Petal or sepal number
- there are five petals, sepals, or tepals in the flower
- Petal color
- yellow
- Specific leaf type
- the leaf is not divided, rather the blade is made up of one segment
- Floating leaf shape
- NA
- Underwater leaf blade width
- 2–8 mm
- Fruit type (general)
- the fruit is dry and splits open when ripe
- Underwater leaf length
- 6–32 mm
-
Clonal plantlets
- Turion length
- 0 mm
-
Flowers
- Anther color
- there is a noticeable pink, reddish or purplish tint to the anthers
- Carpels fused
- the carpels are fused to one another
- Flower lower lip length
- 0 mm
- Flower position
- the flowers are above the surface of the water
- Flower symmetry
- there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
- Inflorescence type
- the inflorescence is a dichasial cyme (an axis with a terminal flower, below it a pair of branches, each with a terminal flower, these branches may in turn have a pair of branches and so on)
- Nectar spur
- the flower has no nectar spurs
- Number of carpels
- 3–4
- Ovary position
- the sepals and/or petals are attached below the ovary
- Palate on corolla
- no
- Petal and sepal arrangement
- the flower includes two cycles of petal- or sepal-like structures
- Petal appearance
- the petals are thin and delicate, and pigmented (colored other than green or brown)
- Petal color
- yellow
- Petal fringed edges
- the petals are not fringed
- Petal fusion
- the perianth parts are separate
- Petal hairs on inner/upper surface
- there are no hairs on the inner/upper petal surface
- Petal length
- 2.5–3 mm
- Petal number
- 5
- Petal or sepal number
- there are five petals, sepals, or tepals in the flower
- Pistil number
- 1
- Sepal appearance
- the sepals resemble leaves in color and texture
- Sepal number
- 5
- Sepals fused only to sepals
- the sepals are separate from one another
- Spur length
- 0 mm
- Stamen number
-
- 10
- 11
- 12
- 13 or more
- 8
- 9
- Stamen position relative to petals
- NA
- Stamens fused
- the stamens are not fused to one another
- Stamens fused to petals
- the stamens are not fused to the petals or tepals
- Style length
- Up to 1 mm
- Style number
- 3–4
-
Fruits or seeds
- Fruit beak length
- 0 mm
- Fruit length
- 3–5 mm
- Fruit type (general)
- the fruit is dry and splits open when ripe
- 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)
-
Glands or sap
- Oil glands on nodes
- none of the nodes have oil glands
- Sap
- the sap is clear and watery
-
Growth form
- Lifespan
- the plant lives more than two years
- Root septa
- the roots do not have transverse septa
- Roots floating in water
- there are no clusters of roots floating in the water
- Turions
- there are no turions on the plant
- Underground organs
- the plant has a rhizome (a horizontal underground stem with roots growing from it)
-
Leaves
- Bract position (Sparganium)
- NA
- Bracts
- the flowers or their pedicels have bracts at their bases
- Floating leaf basal lobes
- NA
- Floating leaf blade width
- 0 mm
- Floating leaf length
- 0 mm
- Floating leaf shape
- NA
- Floating leaf tip
- NA
- Floral bract form
- the bracts are roughly as lobed as the foliage leaves
- Leaf arrangement
- opposite: there are two leaves per node along the stem
- Leaf blade length
- 6–34 mm
- Leaf blade veins
- the lateral veins radiate from the base and continue to spread away from the centerline of the leaf, or branch off the central vein at intervals
- Leaf blade width
- 2–8 mm
- Leaf position
- the leaves are all submerged underwater
- Leaf special features
- none of the mentioned special features are present
- Leaf-like branch segments
- 0
- Leaf-like branch shape
- NA
- Specific leaf type
- the leaf is not divided, rather the blade is made up of one segment
- Staminate bract edge (Myriophyllum)
- NA
- Stipule appearance
- NA
- Stipule fused to leaf
- NA
- Stipules
- there are no stipules on the plant
- Stipules fused around stem
- NA
- Trap-bladder length
- 0 mm
- Underwater leaf air passage number
- At least 1439
- Underwater leaf air passage relative width
- At least 4336
- Underwater leaf air passage row number
- 0
- Underwater leaf blade edges
- the underwater leaf has smooth edges, without teeth
- Underwater leaf blade shape
-
- the underwater leaf blade is elliptic (widest near the middle and tapering at both ends)
- the underwater leaf blade is oblong (rectangular but with rounded ends)
- the underwater leaf blade is ovate (widest below the middle and broadly tapering at both ends)
- Underwater leaf blade veins
- 3–5
- Underwater leaf blade width
- 2–8 mm
- Underwater leaf length
- 6–32 mm
- Underwater leaf stalk
- no
- Underwater leaf stalk length
- 0 mm
- Underwater leaf tip shape
-
- the tip of the underwater leaf is obtuse (bluntly pointed)
- the tip of the underwater leaf is rounded, with no point
- Veins in floating leaf
- 0
-
Place
- Habitat
-
- aquatic
- wetlands
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- edges of wetlands
- in lakes or ponds
- shores of rivers or lakes
- swamps
-
Stem, shoot, branch
- Flowering stem growth form
-
- the flowering stem is upright
- the flowering stem trails along the substrate, or floats in the water
Wetland status
Occurs only in wetlands. (Wetland indicator code: OBL)
New England distribution and conservation status
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
- widespread (S-rank: S5)
Native to North America?
Yes and no (some introduced)
Sometimes confused with
- Hypericum canadense:
- capsule pointed at apex and sepals broadest below the middle (vs. H. boreale, with the capsule rounded at apex and sepals broadest near middle).
- Hypericum majus:
- capsule pointed at apex and sepals broadest below the middle (vs. H. boreale, with the capsule rounded at apex and sepals broadest near middle).
- Hypericum mutilum:
- bracts of inflorescence tiny, not resembling the leaves and sepals approximately as long as the capsule (vs. H. boreale, with the bracts of inflorescence leaf-like and sepals shorter than the capsule).
Synonyms
- Hypericum mutilum ssp. boreale (Britt.) J. Gillett
Family
Genus
From the dichotomous key of Flora Novae Angliae
3. Hypericum boreale (Britt.) Bickn. N
northern St. John’s-wort. Hypericum mutilum L. ssp. boreale (Britt.) J. Gillett • CT, MA, ME, NH, RI, VT. Shorelines, swamps, wetland edges.
3×4. Hypericum boreale × Hypericum canadense → Hypericum ×dissimulatum Bickn. is an uncommon St. John’s-wort hybrid known from CT, MA, ME, RI, VT. It is frequently sterile (at least partially, the capsules not filled with well-formed seeds). It generally resembles H. canadense, but the leaf blades average wider (1.5–10 mm vs. 1–4 (–6) mm) and the capsule is usually shorter (3–4.5 mm vs. 4–6 (–6.5) mm) and relatively blunter (i.e., intermediate in shape between the two parents).