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

Hypericum adpressum — creeping St. John's-wort

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New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Facts

Creeping St. John's-wort is found in a number of eastern and midwestern states, but it is uncommon to rare throughout most of its distribution. In New England, it inhabits mainly coastal plain pond shores and riversides in Connecticut, Massachusetts and Rhode Island. Of all documented occurrences, nearly one half are now lost, so the species is in apparent decline in New England. Its pondshore habitat, which supports a number of other rare plant species, is vulnerable to residential development and recreation.

Habitat

Shores of rivers or lakes, wetland margins (edges of wetlands)

Characteristics

Habitat
  • terrestrial
  • wetlands
Flower petal color
yellow
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 are two or more ways to evenly divide the flower (the flower is radially symmetrical)
  • there is no way to evenly divide the flower (the flower is asymmetrical)
Number of sepals, petals or tepals
there are five petals, sepals, or tepals in the flower
Fusion of sepals and petals
both the petals and sepals are separate and not fused
Stamen number
13 or more
Fruit type (general)
the fruit is dry and splits open when ripe
Fruit length
2–7 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

    Anther opening
    the anthers have narrow slits or furrows that run lengthwise along the anthers
    Anther spurs
    the anthers do not have spurs on them
    Calyx symmetry
    there are two or more ways to evenly divide the calyx (the calyx is radially symmetrical)
    Carpel hairs
    the carpels have no hairs
    Carpels fused
    the carpels are fused to one another
    Cleistogamous flowers
    there are no cleistogamous flowers on the plan
    Corolla morphology
    NA
    Corolla palate
    no
    Corona lobe length
    0 mm
    Epicalyx
    the flower does not have an epicalyx
    Epicalyx number of parts
    0
    Filament surface
    the filament is smooth, with no hairs or scales
    Flower description
    the flower has a superior ovary, and lacks a hypanthium
    Flower petal color
    yellow
    Flower reproductive parts
    the flower has both pollen- and seed-producing parts
    Flower symmetry
    • there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
    • there is no way to evenly divide the flower (the flower is asymmetrical)
    Flowers sunken into stem
    no
    Form of style
    the style is narrow at the tip and unbranched
    Fused stamen clusters
    NA
    Fusion of sepals and petals
    both the petals and sepals are separate and not fused
    Hairs on flower stalk
    the flower stalk has no hairs on it
    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 carpels
    2–4
    Number of pistils
    3
    Number of sepals, petals or tepals
    there are five petals, sepals, or tepals in the flower
    Number of styles
    3–4
    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
    yellow
    Petal appearance
    the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal folding in bud
    the petals in bud are rolled like an umbrella, each petal having one edge tucked inside and the other edge exposed (convolute)
    Petal folds or pleats
    the petals of the flower do not have folds or plaits
    Petal hairs (Viola)
    NA
    Petal length
    5–8 mm
    Petal length relative to sepals
    the petals are longer than the sepals
    Petal number
    5
    Petal tips (Cuscuta)
    NA
    Scales inside corolla
    no
    Sepal and petal color
    the sepals are different from the petals
    Sepal appearance
    the sepals are green or brown, and leaf-like in texture
    Sepal appendages
    the sepals do not have appendages on them
    Sepal appendages (Oenothera)
    NA
    Sepal color
    green to brown
    Sepal number
    5
    Sepal relative length
    NA
    Sepal shape
    • the sepal outline is lanceolate (lance-shaped; narrow, gradually tapering from the base to the tip)
    • the sepal outline is ovate (widest below the middle and broadly tapering at both ends)
    Sepal uniformity
    all the sepals are about the same size
    Sepals fused only to sepals
    the sepals are separate from one another
    Stamen number
    13 or more
    Stamens fused
    the stamens are not attached to one another
    Staminodes
    there are no staminodes on the flower
    Style petal-like
    the styles are not petal-like
    Umbel flower reproductive parts
    NA
    Upper lip of bilabiate corolla
    NA

  • 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 three main valves, teeth or pores
    Fruit (pyxis) dehiscence
    NA
    Fruit beak length
    anything
    Fruit features (Brassicaceae)
    NA
    Fruit length
    2–7 mm
    Fruit locules
    one
    Fruit shape
    the fruit is ovoid (egg-shaped)
    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)
    Hair type on fruit
    NA
    Hairs on fruit
    the fruits are not hairy
    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 parietal placentation, where ovules develop on the wall or slight outgrowths of the wall forming broken partitions within a compound ovary
    Rows of seeds in fruit (Brassicaceae)
    NA
    Schizocarpic fruit compression
    NA
    Schizocarpic fruit segments
    0
    Seed length
    0.7–0.8 mm
    Seed surface
    the seed is smooth or without clear markings
    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
    • the leaf blades 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
    Parasitism
    the plant is not parasitic
    Plant color
    the leaves or young stems of the plant are green
    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
    Floral bracts
    the flower has one or more bracts associated with it
    Hairs on leaf stalk
    NA
    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
    Hooked hairs on underside of leaf
    NA
    Inflated hairs on leaf
    NA
    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 base symmetry
    the leaf blade base is symmetrical
    Leaf blade edges
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf blade flatness
    the edges of the leaf are curled under
    Leaf blade hairs
    NA
    Leaf blade length
    30–60 mm
    Leaf blade primary vein pattern
    the secondary veins branch off at intervals from the primary vein
    Leaf blade shape
    • the leaf blade is elliptic (widest near the middle and tapering at both ends)
    • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
    • the leaf blade is oblong (rectangular but with rounded ends)
    Leaf blade surface colors
    the upper side of the leaf blade is relatively uniform in color
    Leaf blade texture
    the leaf blade is herbaceous (has a leafy texture)
    Leaf blade vein pattern
    the major veins form a net-like pattern due to splitting and rejoining
    Leaf blade veins
    the leaf blade has one main vein running from the base towards the tip (it may or may not have secondary veins)
    Leaf blade width
    5–10 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 hair orientation
    NA
    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 stalk attachment to leaf
    NA
    Leaf stalk base
    NA
    Leaf teeth and lobes
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf tip
    the tip of the leaf blade is acute (sharply pointed)
    Leaf type
    the leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
    Leaf variation
    the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
    Leaflet number
    0
    Leaflet petiolules
    NA
    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)
    Stipule edges
    NA
    Stipule features
    NA
    Stipule fused to leaf stalk
    NA
    Stipule shape
    NA
    Stipules
    there are no stipules on the plant
    Teeth per side of leaf blade
    0

  • Place

    Habitat
    • terrestrial
    • wetlands
    Specific habitat
    • edges of wetlands
    • shores of rivers or lakes

  • Scent

    Plant odor
    the plant does not have much of a smell

  • Stem, shoot, branch

    Branched tendrils
    NA
    Direction of stem hairs
    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
    Hooked hairs on stem between nodes
    no
    Leaves on stem
    there is at least one full leaf above the base of the flowering stem
    Plant height
    30–80 cm
    Stem hair distribution
    NA
    Stem orientation
    the stems are upright or angled outwards
    Stem roughness between nodes
    the stem does not feel rough
    Stem spacing
    the plant is solitary, or a few plants are growing together
    Tendril origin
    NA
    Tendrils
    the plant does not have tendrils

Wetland status

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

New England distribution and conservation status

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.

Connecticut
historical (S-rank: SH), special concern, extirpated (code: SC*)
Massachusetts
rare (S-rank: S2), threatened (code: T)
Rhode Island
rare (S-rank: S2), state threatened (code: ST)

Native to North America?

Yes

Sometimes confused with

Hypericum ellipticum:
leaf blades with flat margins, elliptic to elliptic-oblong, mostly 1–3 cm long, 2–3 times as long as wide, and sepals oblanceolate to narrow-obovate, widest above the middle (vs. H. adpressum, with leaf blades with revolute margins, narrow-lanceolate to narrow-oblong or narrow-elliptic, 3–6 cm long, 4–6 times as long as wide, and sepals lanceolate to ovate, widest near or below the middle).

Family

Hypericaceae

Genus

Hypericum

Help

From the dichotomous key of Flora Novae Angliae

1.  Hypericum adpressum Raf. ex Bart. NC

creeping St. John’s-wort. CT, MA, RI; coastal plain. River shores, coastal plain pond shores, sandy and peaty depressions.