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

Clematis terniflora — yam-leaved virgin's-bower

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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

Yam-leaved virgin's-bower hails from Japan and is introduced in North America. In New England, it is known from all states except Maine. This is a vigorous climber (when it cannot climb, it sprawls and creates dense ground cover), which produces large numbers of showy, white flowers in the fall. It also produces large numbers of seeds, each bearing a silver, feathery tail that aids in dispersal. Because of its "rampant" growth and tendency to self-seed outside the garden, this species is regarded as invasive in parts of its North American range.

Habitat

Forest edges, forests, meadows and fields

Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Flower petal color
NA
Leaf type
the leaves are compound (made up of two or more discrete 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)
Number of sepals, petals or tepals
there are four 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 but does not split open when ripe
Fruit length
5–9 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)
    Carpels fused
    the carpel is solitary or (if 2 or more) the carpels are not fused to one another
    Cleistogamous flowers
    there are no cleistogamous flowers on the plan
    Corolla morphology
    NA
    Corolla palate
    NA
    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
    NA
    Flower symmetry
    there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
    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
    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 pistils
    • 5
    • 6 or more
    Number of sepals, petals or tepals
    there are four petals, sepals, or tepals in the flower
    Number of styles
    1
    Ovary position
    the ovary is above the point of petal and/or sepal attachment
    Petal and sepal arrangement
    the flower includes only one cycle of petals or sepals
    Petal and sepal colors
    white
    Petal appearance
    NA
    Petal folds or pleats
    • NA
    • the petals of the flower do not have folds or plaits
    Petal hairs (Viola)
    NA
    Petal number
    0
    Petal tip shape
    • NA
    • the petal tip is obtuse (bluntly pointed)
    • the petal tip is rounded
    • the petal tip is truncate (ends abruptly in a more or less straight line as though cut off)
    Petal tips (Cuscuta)
    NA
    Reproductive system
    • all the flowers have both carpels and stamens (synoecious)
    • the plant has flowers with both carpels and stamens, as well as flowers with only carpels or only stamens (polygamous)
    Scales inside corolla
    NA
    Sepal and petal color
    NA
    Sepal appendages
    the sepals do not have appendages on them
    Sepal appendages (Oenothera)
    NA
    Stamen attachment
    the stamens are not attached to the petals or tepals
    Stamen number
    13 or more
    Stamen position relative to petals
    NA
    Umbel flower reproductive parts
    NA
    Upper lip of bilabiate corolla
    NA

  • Fruits or seeds

    Achene relative orientation
    the achenes are perpendicular to the plane of the perianth (vertical)
    Achene shape
    the achenes are another shape in outline
    Achene surface (Polygonum)
    NA
    Achene type
    the fruit is an achene (dry, indehiscent, and usually one-seeded)
    Berry color
    NA
    Capsule color (Viola)
    NA
    Capsule ribs
    NA
    Capsule splitting
    NA
    Fruit (pyxis) dehiscence
    NA
    Fruit features (Brassicaceae)
    NA
    Fruit length
    5–9 mm
    Fruit locules
    one
    Fruit type (general)
    the fruit is dry but does not split open when ripe
    Fruit type (specific)
    the fruit is an achene (dry, usually one-seeded, does not separate or split open at maturity)
    Legumes (Fabaceae)
    NA
    Mericarp length
    0 mm
    Mericarp segment shape (Desmodium)
    NA
    Other markings on berry
    NA
    Placenta arrangement
    • marginal
    • the plant has basal placentation, where one or a few ovules develop at the base of a simple or compound ovary
    Rows of seeds in fruit (Brassicaceae)
    NA
    Schizocarpic fruit compression
    NA
    Schizocarpic fruit segments
    0
    Septum in fruit (Brassicaceae)
    NA
    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
    Sap
    the sap is clear and watery
    Sap color
    the sap is clear

  • Growth form

    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
    Plants darken when dry
    no
    Spines on plant
    the plant has no spines

  • Leaves

    Bracteole number (Apiaceae)
    0
    Bracts in plantain (Plantago)
    NA
    Hairs on underside of leaf
    the underside of the leaf is not hairy, or it has very few hairs
    Leaf arrangement
    opposite: there are two leaves per node along the stem
    Leaf blade base
    the leaf has a distinct leaf stalk (petiole)
    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 edges
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf blade length
    Up to 120 mm
    Leaf blade shape
    • the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
    • the leaf blade is ovate (widest below the middle and broadly tapering at both ends)
    • the leaf blade is triangular, with the stalk or attachment point on one of the sides
    Leaf blade surface colors
    the upper side of the leaf blade is relatively uniform in color
    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 spines
    there are no spines on the leaf edges
    Leaf stalk attachment to leaf
    the petiole attaches at the basal margin of the leaf blade
    Leaf stalk base
    the petiole base is narrow where it attaches to the stem
    Leaf teeth and lobes
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf type
    the leaves are compound (made up of two or more discrete leaflets
    Leaf variation
    the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
    Leaflet number
    3–5
    Leaves per node
    there are two leaves per node along the stem
    Pinnately compound leaf type
    the pinnately compound leaves have a terminal leaflet (and usually have an odd number of leaflets per axis)
    Specific leaf type
    the leaf has a row of two or more lobes on each side of the central axis
    Stipels
    there are no stipels at the bases of the petiolules
    Stipule features
    NA
    Stipules
    there are no stipules on the plant

  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • edges of forests
    • forests
    • meadows or fields

  • Scent

    Plant odor
    the plant does not have much of a smell

  • Stem, shoot, branch

    Branched tendrils
    NA
    Flowering stem cross-section
    • the flowering stem has strong or sharp angles, but is not square
    • the flowering stem is circular, or with lots of small angles so that it is roughly circular
    Hair between stem nodes
    the stem has no hairs between the nodes
    Leaves on stem
    there is at least one full leaf above the base of the flowering stem
    Plant height
    300–600 cm
    Tendril origin
    NA
    Tendrils
    the plant does not have tendrils

Wetland status

Occurs only in non-wetlands. (Wetland indicator code: UPL)

New England distribution and conservation status

Distribution

Connecticut
present
Maine
absent
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
not applicable (S-rank: SNA)

Native to North America?

No

Sometimes confused with

Clematis vitalba:
sepals tomentose adaxially, leaf margins entire to crenate or dentate, and flowers with 20 or more carpels (vs. C. terniflora, with sepals glabrous adaxially, leaflet margins entire, and flowers with 10 or fewer carpels).
Clematis virginiana:
flowers unisexual, the carpellate ones with 40-70 carpels, and leaves with 3 leaflets (vs. C. terniflora, with flowers bisexual or sometimes some of them unisexual and then staminate, the bisexual ones with 5-10 carpels, and leaves with 3 or 5 leaflets).

Synonyms

  • Clematis dioscoreifolia Levl. & Vaniot
  • Clematis dioscoreifolia Levl. & Vaniot var. robusta (Carr.) Rehd.
  • Clematis paniculata Thunb.

Family

Ranunculaceae

Genus

Clematis

Help

From the dichotomous key of Flora Novae Angliae

4.  Clematis terniflora DC. E

yam-leaved virgin’s-bower. Clematis dioscoreifolia Levl. & Vaniot; C. dioscoreifolia Levl. & Vaniot var. robusta (Carr.) Rehd.; C. paniculata Thunb. • CT, MA, NH, RI, VT. Roadsides, fields, forest fragments, near dwellings.