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

Ballota nigra — black-horehound

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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

Black-horehound is native to Europe and northern Africa and is introduced to scattered locations in North America. It has a long history of use as a medicinal herb in Europe, although it is less used today. It has been used to treat motion sickness and morning sickness among other applications. Several varieties have been named, and two have been collected in New England, probably as escapes from cultivation.

Habitat

Anthropogenic (man-made or disturbed habitats)

Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Massachusetts
Flower petal color
  • blue to purple
  • pink to red
  • white
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 has teeth
Flower symmetry
there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
Number of sepals, petals or tepals
there are five petals, sepals, or tepals in the flower
Fusion of sepals and petals
the petals or the sepals are fused into a cup or tube
Stamen number
4
Fruit type (general)
the fruit is dry but does not split open when ripe
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

    Calyx symmetry
    there are two or more ways to evenly divide the calyx (the calyx is radially symmetrical)
    Carpels fused
    the carpels are fused to one another
    Cleistogamous flowers
    there are no cleistogamous flowers on the plan
    Corolla palate
    no
    Corona lobe length
    0 mm
    Epicalyx
    the flower does not have an epicalyx
    Epicalyx number of parts
    0
    Flower description
    the flower has a superior ovary, and lacks a hypanthium
    Flower number
    4–8
    Flower petal color
    • blue to purple
    • pink to red
    • white
    Flower reproductive parts
    • the flower has both pollen- and seed-producing parts
    • the flower has either only pollen- or only seed-producing parts
    Flower symmetry
    there is only one way to evenly divide the flower (the flower is bilaterally symmetrical)
    Flowers sunken into stem
    no
    Form of style
    the style is branched above the base
    Fused stamen clusters
    NA
    Fusion of sepals and petals
    the petals or the sepals are fused into a cup or tube
    Horns in hoods (Asclepias)
    NA
    Hypanthium
    the flower does not have a hypanthium
    Inner tepals (Rumex)
    NA
    Length of peduncle
    2–5 mm
    Nectar spur
    the flower has no nectar spurs
    Number of carpels
    2
    Number of sepals, petals or tepals
    there are five 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 two cycles of petal- or sepal-like structures
    Petal and sepal colors
    • blue to purple
    • pink to red
    • white
    Petal appearance
    the petals are thin and delicate, and pigmented (colored other than green or brown)
    Petal folds or pleats
    the petals of the flower do not have folds or plaits
    Petal hairs (Viola)
    NA
    Petal hairs on inner/upper surface
    there are hairs on the inner/upper petal surface
    Petal length
    9–15 mm
    Petal number
    5
    Petal tip shape
    • the petal tip is retuse (with a blunt or rounded apex and a notch at the center)
    • the petal tip is rounded
    Petal tips (Cuscuta)
    NA
    Reproductive system
    all the flowers have both carpels and stamens (synoecious)
    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 features
    one or more sepals have a spine at the tip
    Sepal length
    7–13 mm
    Sepal number
    5
    Sepal orientation
    the sepals are pressed against the corolla, or jutting stiffly upward
    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)
    • the sepal outline is roughly triangular
    • the sepal outline is subulate (narrowly tapering from the base to the apex; awl-shaped)
    Sepal tip shape
    the sepal tip is notched
    Sepals fused only to sepals
    the sepals are fused to each other (not other flower parts), at least near their bases
    Stamen attachment
    the stamens are attached at or near the bases of the petals or tepals
    Stamen morphology
    the stamens within a cycle differ in length or width
    Stamen number
    4
    Stamen relative length
    anything
    Stamens fused
    the stamens are not attached to one another
    Stigma position
    the stigmas are positioned at the tip of the style
    Style petal-like
    the styles are not petal-like
    Umbel flower reproductive parts
    NA
    Upper lip of bilabiate corolla
    the upper lip of the bilabiate corolla has two lobes

  • 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 ribs
    NA
    Capsule splitting
    NA
    Fruit (pyxis) dehiscence
    NA
    Fruit beak length
    0 mm
    Fruit features (Brassicaceae)
    NA
    Fruit locules
    four
    Fruit shape
    • the fruit is obloid (longer than wide and with rounded ends)
    • the fruit is spherical
    Fruit type (general)
    the fruit is dry but does not split open when ripe
    Fruit type (specific)
    the fruit is a schizocarp (when dry it splits into sections, each holding one or more seeds)
    Hair type on fruit
    NA
    Hairs on fruit
    the fruits are not hairy
    Legumes (Fabaceae)
    NA
    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 axile placentation, in which the ovules are attached where the septa of a compound ovary are united, usually on the central axis, or to the septa themselves
    Rows of seeds in fruit (Brassicaceae)
    NA
    Schizocarpic fruit compression
    the fruit is not flattened
    Schizocarpic fruit segments
    4
    Seed number
    1–4
    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 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

  • Leaves

    Bracteole length
    3–9 mm
    Bracteole number (Apiaceae)
    0
    Bracteole shape
    • the bracteoles are linear (very narrow, with more or less parallel sides)
    • the bracteoles are subulate (narrowly tapering from the base to the apex; awl-shaped)
    Bracteoles
    the plant has bracteoles between the primary bracts and the flowers
    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
    Hairs on underside of leaf
    • the underside of the leaf is fuzzy or hairy
    • 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 cordate (heart-shaped, has rounded lobes at the base)
    • 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 has teeth
    Leaf blade length
    30–80 mm
    Leaf blade primary vein pattern
    the secondary veins branch off at intervals from the primary vein
    Leaf blade shape
    • the leaf blade is oblong (rectangular but with rounded ends)
    • the leaf blade is ovate (widest below the middle and broadly tapering at both 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 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
    20–60 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 spines
    there are no spines on the leaf edges
    Leaf stalk
    the leaves have leaf stalks
    Leaf stalk length
    Up to 50 mm
    Leaf teeth and lobes
    the leaf blade margin has outward-pointing teeth
    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)
    Stipels
    NA
    Stipule features
    NA
    Stipules
    there are no stipules on the plant

  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Massachusetts
    Specific habitat
    man-made or disturbed habitats

  • Scent

    Plant odor
    the plant has a pleasant smell, for example anise, fruit, mint or resin

  • Stem, shoot, branch

    Branched tendrils
    NA
    Flowering stem cross-section
    the flowering stem is roughly square
    Hair between stem nodes
    • the stem has hairs between the 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
    Up to 130 cm
    Stem orientation
    the stems are upright or angled outwards
    Stem spacing
    the plant is growing in tufts, or compact clusters with closely spaced stems, or it is densely matted together in clumps, cushionlike
    Tendril origin
    NA
    Tendrils
    the plant does not have tendrils

Wetland status

Not classified

New England distribution and conservation status

Distribution

Connecticut
present
Maine
absent
Massachusetts
present
New Hampshire
absent
Rhode Island
absent
Vermont
absent

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

var. nigra

Massachusetts
not applicable (S-rank: SNA)

Native to North America?

No

Sometimes confused with

Glechoma hederacea:
stems prostrate or trailing and each flower-bearing axil with usually 3 flowers (vs. B. nigra, with stems erect and each flower-bearing axil with 4-8 flowers).

Synonyms

  • Ballota nigra L. var. ruderalis (Sw.) Koch

Family

Lamiaceae

Genus

Ballota

Notes on subspecies and varieties in New England

Variety alba is known from CT. It has often been referred to by the epithet foetida, but this name does not have priority at the varietal rank. Variety nigra is known from MA.

Help

From the dichotomous key of Flora Novae Angliae

1.  Ballota nigra L. E

black-horehound. 1a. Ballota alba L.; B. borealis Schweig.; B. nigra L. ssp. foetida (Koch) Hayek; 1b. Ballota nigra L. var. ruderalis (Sw.) Koch • CT, MA. Dumps, waste areas.

1a.  Calyx lobes 1.5–3 mm long excluding the mucros, ovate to triangular-ovate, with a tiny mucro at the apex 0.2–0.5 (–1.7) mm long … 1a. B. nigra var. alba (L.) Sm.

1b.  Calyx lobes (3–) 4–6.5 mm long excluding the awns, triangular-lanceolate to subulate-lanceolate, with a prolonged awn at the apex 1.5–3 mm long … 1b. B. nigra var. nigra

Variety alba is known from CT. It has often been referred to by the epithet foetida, but this name does not have priority at the varietal rank. Variety nigra is known from MA.