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

Agalinis tenuifolia — slender-leaved agalinis, slender-leaved false-foxglove

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Facts

Slender-leaved agalinis is an example of a partial plant parasite. It establishes a connection between its roots and those of a host plant using specialized roots called haustoria. These transfer sugars and proteins from the host plant to the parasite. Slender-leaved agalinis is only partially parasitic because it has green tissues and performs photosynthesis.

Habitat

Anthropogenic (man-made or disturbed habitats), meadows and fields, woodlands

New England distribution

Adapted from BONAP data

Found this plant? Take a photo and post a sighting.

North America distribution

Adapted from BONAP data

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Characteristics

Habitat
terrestrial
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • Vermont
Flower petal color
  • blue to purple
  • pink to red
  • white
Leaf type
the leaves are simple (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 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
Stem nodes swollen
the stem is not swollen at the nodes
Fruit type (general)
the fruit is dry and splits open when ripe
Fruit length
3–7 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 color
    the anthers show no hint of a pink, reddish or purplish tint
    Anther length
    1.5–2.2 mm
    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
    Anther tube length
    0 mm
    Calyx growth after flowering
    the calyx does not grow to cover or partially cover the fruit
    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
    Cilia on petals
    the petal margins have cilia
    Cleistogamous flowers
    there are no cleistogamous flowers on the plan
    Corolla morphology
    the flower has two prominent lips
    Corolla palate
    no
    Corona lobe length
    0 mm
    Epicalyx
    the flower does not have an epicalyx
    Epicalyx number of parts
    0
    Filament length
    2–6 mm
    Filament surface
    • the filament has rough hairs or scales on it
    • the filament is smooth, with no hairs or scales
    Flower description
    the flower has a superior ovary, and lacks a hypanthium
    Flower orientation
    the flower points upwards or is angled outwards
    Flower petal color
    • blue to purple
    • pink to red
    • white
    Flower reproductive parts
    the flower has both pollen- and 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 narrow at the tip and unbranched
    Fringed petal edges
    the petals are not fringed
    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
    Hypanthium length
    0 mm
    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
    Interior flower disk
    the flower does not have an interior disc
    Length of flower stalk
    10–20 mm
    Marks on petals
    the petals have spots or streaks on them
    Nectar spur
    the flower has no nectar spurs
    Number of branches in umbel
    0
    Number of carpels
    2
    Number of pistils
    1
    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
    Perianth shape
    • the perianth is campanulate (bell-shaped, with a tube about as long as wide, flaring at the mouth)
    • the perianth is funnelform (funnel-shaped)
    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 base
    • NA
    • the petal narrows gradually or does not narrow at the base
    Petal folding in bud
    the petals in bud are arranged in a cycle with edges overlapping like roof shingles (imbricate)
    Petal folds or pleats
    the petals of the flower do not have folds or plaits
    Petal glandular dots or scales
    no
    Petal hairs (Viola)
    NA
    Petal hairs on inner/upper surface
    there are no hairs on the inner/upper petal surface
    Petal length
    10–15 mm
    Petal length relative to sepals
    the petals are longer than the sepals
    Petal nectaries
    the petals do not have nectaries
    Petal number
    5
    Petal shape
    the petal outline is another shape
    Petal tip shape
    the petal tip is lobed or fringed
    Petal tips (Cuscuta)
    NA
    Raceme attachment (Veronica)
    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 auricles
    the sepals have no auricles
    Sepal cilia
    the sepals do not have cilia
    Sepal color
    green to brown
    Sepal features
    NA
    Sepal length
    0.2–3.5 mm
    Sepal number
    5
    Sepal orientation
    the sepals are pressed against the corolla, or jutting stiffly upward
    Sepal relative length
    the sepal lobes are shorter than the fused portion
    Sepal shape
    • the sepal outline is roughly triangular
    • the sepal outline is subulate (narrowly tapering from the base to the apex; awl-shaped)
    Sepal texture
    the sepals are either very thin but flexible, like a membrane, or they are leaf-like in texture
    Sepal tip shape
    • the sepal tip is acuminate (tapers to a very narrow point)
    • the sepal tip is acute (is sharply pointed)
    Sepal uniformity
    all the sepals are about the same size
    Sepals fused only to sepals
    the sepals are fused to each other (not other flower parts), at least near their bases
    Spur length
    0 mm
    Spur number
    NA
    Stamen appendages
    stamen appendages are absent
    Stamen attachment
    • the stamens are attached at or near the bases of the petals or tepals
    • the stamens are attached at or near the bases of the petals or tepals
    Stamen lengths differ
    the stamens are didynamous (two long stamens and two short ones)
    Stamen morphology
    the stamens within a cycle differ in length or width
    Stamen number
    4
    Stamen position relative to petals
    NA
    Stamen relative length
    anything
    Stamens fused
    the stamens are not attached to one another
    Staminodes
    there are no staminodes on the flower
    Stigma length
    1–1.5 mm
    Stigma position
    the stigmas are positioned at the tip of the style
    Style length
    8–14 mm
    Style petal-like
    the styles are not petal-like
    Style relative length
    the stigma does not protrude beyond the mouth of the corolla
    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
    the capsule has two prominent ribs or wings
    Capsule splitting
    the capsule splits by two main valves, teeth or pores
    Fruit (pyxis) dehiscence
    NA
    Fruit cross-section
    the fruit is round in cross-section
    Fruit features (Brassicaceae)
    NA
    Fruit length
    3–7 mm
    Fruit length relative to sepals
    the fruit is longer than its associated sepals
    Fruit locules
    two
    Fruit shape
    the fruit is spherical
    Fruit stalk orientation
    the fruits point upward or spread or curve outward
    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
    the hairs on the fruits are simple (not branched), don’t have glands, and are not woolly
    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
    Ovary stipe length
    0 mm
    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
    NA
    Schizocarpic fruit segments
    0
    Seed length
    0.6–1.3 mm
    Seed surface
    • the seed is covered with reticulate markings (a netlike pattern due to splitting and rejoining of lines or ridges)
    • the seed is smooth or without clear markings
    Seeds comose
    no hairs
    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
    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)
    Horizontal rooting stem
    the plant does not have stolons
    Lifespan
    the plant lives only a single year or less
    Parasitism
    the plant is parasitic on other plants (partially or completely dependent on other plants to supply nutrients)
    Plant color
    the leaves or young stems of the plant are green
    Plants darken when dry
    yes
    Spines on plant
    the plant has no spines
    Underground organs
    there are only slender roots on the plant

  • 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 fuzzy or hairy
    Hooked hairs on underside of leaf
    no
    Inflated hairs on leaf
    the leaf blade does not have inflated hairs on it
    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 bloom
    the underside of the leaf has no noticeable bloom
    Leaf blade edges
    the edge of the leaf blade is entire (has no teeth or lobes)
    Leaf blade flatness
    the leaf is flat (planar) at the edges
    Leaf blade hairs
    the leaf blade has simple hairs with no glands, and not tangled or wooly
    Leaf blade length
    20–50 mm
    Leaf blade primary vein pattern
    the secondary veins branch off at intervals from the primary vein
    Leaf blade shape
    the leaf blade is linear (very narrow with more or less parallel sides)
    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
    NA
    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
    1–3.5 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
    the hairs are flat against the leaf surface, mostly pointing towards the leaf tip
    Leaf sheath length
    0 mm
    Leaf shiny
    the upper side of the leaf is dull or slightly shiny
    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 stalk length
    0 mm
    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 acuminate (tapers to a long, thin point)
    Leaf tufts in axils
    • there are clusters of smaller leaves growing out of axils
    • there are no clusters of smaller leaves growing out of axils
    Leaf type
    the leaves are simple (lobed or unlobed but not separated into leaflets)
    Leaf types
    There is a gradual change in appearance of the leaves from the base (or near the base) of the plant to those from further up on the stem, with leaves progressively changing as one moves higher on the stem (often becoming shorter, or less toothed/lobed, and/or with shorter petioles).
    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 (lobed or unlobed but not separated into leaflets)
    Stipels
    NA
    Stipule edges
    NA
    Stipule features
    NA
    Stipule fused to leaf stalk
    NA
    Stipule length
    0 mm
    Stipule shape
    NA
    Stipules
    there are no stipules on the plant
    Teeth per side of leaf blade
    0

  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • man-made or disturbed habitats
    • meadows or fields
    • woodlands

  • Scent

    Plant odor
    the plant does not have much of a smell

  • Stem, shoot, branch

    Branched tendrils
    NA
    Direction of stem hairs
    NA
    Flowering stem cross-section
    the flowering stem is roughly square
    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
    Length of hairs between stem nodes
    0 mm
    Plant height
    20–60 cm
    Stem bloom
    there is no powdery or waxy film on the stem
    Stem hair distribution
    NA
    Stem nodes swollen
    the stem is not swollen at the nodes
    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
    Stem succulence
    the stems are not succulent
    Tendril origin
    NA
    Tendrils
    the plant does not have tendrils
    Wings on stem
    the stem does not have wings on it

Wetland status

Usually occurs in wetlands, but occasionally in non-wetlands. (Wetland indicator code: FACW)

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.

Massachusetts
unranked (S-rank: SNR)
Rhode Island
rare (S-rank: S2), concern (code: C)

var. parviflora

Massachusetts
unranked (S-rank: SNR)

var. tenuifolia

Massachusetts
unranked (S-rank: SNR)

From Flora Novae Angliae dichotomous key

6.  Agalinis tenuifolia (Vahl) Raf. NC

slender-leaved agalinis.  6a. Gerardia tenuifolia Vahl; G. tenuifolia Vahl var. humilis Benth.; 
 G. tenuifolia Vahl var. typica Pennell;  6b. Agalinis besseyana (Britt.) Britt.; Gerardia besseyana Britt.; G. tenuifolia Vahl ssp. macrophylla (Benth.) Pennell; G. tenuifolia Vahl var. macrophylla Benth.;  6c. Gerardia tenuifolia Vahl ssp. parviflora (Nutt.) Pennell; G. tenuifolia Vahl var. parviflora Nutt. • CT, MA, ME, NH, RI, VT. Fields, roadsides, trail edges, woodlands, clearings, open rights-of-way.

1a.  Calyx lobes 0.2–1.3 (–1.5) mm long; capsules 3–4 (–5) mm long; seeds 0.6–0.9 mm long, with very fine reticulations, the seed surface relatively smooth 
 … 6a. A. tenuifolia var. tenuifolia

1b.  Calyx lobes (0.5–) 1–2 mm long; capsules (4–) 5–7 mm long; seeds 0.7–1.3 mm long, with more pronounced reticulations, causing the seed surface to appear rough

2a.  Axillary fascicles not or only slightly developed; filaments pubescent; anthers densely pubescent; leaves and branches spreading; leaf blades slightly scabrous on the adaxial surface … 6b. A. tenuifolia var. macrophylla (Benth.) Blake

2b.  Axillary fascicles usually well-developed; filaments sparsely pubescent to glabrous; anthers sparsely to moderately pubescent; leaves and branches ascending; leaf blades slightly to conspicuously scabrous on the adaxial surface 
 … 6c. A. tenuifolia var. parviflora (Nutt.) Pennell

Variety tenuifolia is known from CT, MA, ME, NH, RI, VT. Variety macrophylla is known from CT. Variety parviflora is known from MA, VT. Both varieties macrophylla and parviflora are of conservation concern.

Native to North America?

Yes

Sometimes confused with

Agalinis paupercula:
flower stalks 1-8 mm long and petals with hairs on the inside surface (vs. A. tenuifolia, with flower stalks 10-20 mm long and petals without hairs on the inside surface). Agalinis purpurea: flower stalks 1-8 mm long and petals with hairs on the inside surface (vs. A. tenuifolia, with flower stalks 10-20 mm long and petals without hairs on the inside surface).

Synonyms

  • Gerardia tenuifolia Vahl

Family

Orobanchaceae

Genus

Agalinis