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- All other flowering non-woody plants
- All other herbaceous, flowering dicots
- Caulophyllum thalictroides
Caulophyllum thalictroides — blue cohosh
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Facts
Blue cohosh is an attractive wildflower, with an unusual display of the spherical blue fruits held stiffly above the leaf canopy. The roots were widely used my Native Americans as an herbal medicine to treat a range of ailments and as a general tonic.
Habitat
Floodplain (river or stream floodplains), forests
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.
Found this plant? Take a photo and post a sighting.
Characteristics
- Habitat
- terrestrial
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Flower petal color
-
- blue to purple
- green to brown
- yellow
- Leaf type
- the leaves are compound (made up of two or more discrete leaflets
- Leaf arrangement
- alternate: there is one leaf per node along the stem
- Leaf blade edges
-
- the edge of the leaf blade has lobes, or it has both teeth and lobes
- 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 six petals, sepals, or tepals in the flower
- Fusion of sepals and petals
- both the petals and sepals are separate and not fused
- Stamen number
- 6
- Fruit type (general)
-
- NA
- the fruit is dry but does not split open when ripe
- Fruit length
- 0 mm
-
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 attachment
- the anther is attached by its base to the filament
- Anther color
- the anthers show no hint of a pink, reddish or purplish tint
- Anther length
- 1 mm
- Anther opening
- the anthers have flaps on them that cover the opening
- 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)
- Carpel hairs
- the carpels have no hairs
- Carpels fused
- the carpel is solitary or (if 2 or more) the carpels are not fused to one another
- Cilia on petals
- the petal margins do not have cilia
- 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 length
- 0.5–1.5 mm
- Filament surface
- the filament is smooth, with no hairs or scales
- Flower appearance
-
- the flowers appear at the same time as the leaves
- the flowers appear before the leaves
- Flower description
- the flower has a superior ovary, and lacks a hypanthium
- Flower length
- 6–20 mm
- Flower number
- 5–70
- Flower orientation
- the flower points upwards or is angled outwards
- Flower petal color
-
- blue to purple
- green to brown
- 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)
- 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
- both the petals and sepals are separate and not fused
- Hairs on flower stalk
- the flower stalk has no hairs on it
- Hairs on inflorescence
- the axis of the inflorescence has no hairs on it
- Horns in hoods (Asclepias)
- NA
- Hypanthium
- the flower does not have a hypanthium
- Hypanthium length
- 0 mm
- Inflorescence length
- 30–60 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
- Length of peduncle
- At least 30 mm
- Marks on petals
- there are no noticeable marks on the petals
- Nectar spur
- the flower has no nectar spurs
- Number of branches in umbel
- 0
- Number of carpels
- 1
- Number of pistils
- 1
- Number of sepals, petals or tepals
- there are six 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 rotate (platter-shaped, the corolla flattened, circular, with nearly horizontally spreading lobes)
- Petal and sepal arrangement
- the flower includes two cycles of petal- or sepal-like structures
- Petal and sepal colors
-
- blue to purple
- green to brown
- yellow
- Petal appearance
- the petals are thin and delicate, and pigmented (colored other than green or brown)
- Petal base
- the petal narrows abruptly 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
- 1–2.5 mm
- Petal length relative to sepals
- the petals are shorter than the sepals
- Petal nectaries
- the petals have at least one nectary
- Petal number
- 6
- Petal shape
- the petal outline is another shape
- Petal tip shape
- the petal tip is rounded
- Petal tips (Cuscuta)
- NA
- Petal width
- 2 mm
- 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
- the sepals resemble petals in color and 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
-
- blue to purple
- green to brown
- yellow
- Sepal features
- the sepals do not have any of the mentioned special features
- Sepal length
- 3–6 mm
- Sepal number
- 6
- Sepal orientation
- the sepals are slightly curved outwards from the corolla
- Sepal relative length
- NA
- Sepal shape
-
- the sepal outline is oblong (rectangular, but with rounded ends)
- the sepal outline is ovate (widest below the middle and broadly tapering at both ends)
- the sepal outline is spatulate (roughly spoon-shaped; narrow near the base, suddenly widening to a rounded tip)
- 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 rounded
- Sepal uniformity
- all the sepals are about the same size
- Sepals fused only to sepals
- the sepals are separate from one another
- Spur length
- 0 mm
- Spur number
- NA
- Stamen appendages
- stamen appendages are absent
- Stamen attachment
- the stamens are not attached to the petals or tepals
- Stamen lengths differ
- the stamens are all approximately the same length
- Stamen morphology
- the stamens within each cycle are the same
- Stamen number
- 6
- Stamen position relative to petals
- the stamens are lined up with the petals
- Stamen relative length
- anything
- Stamens fused
- the stamens are not attached to one another
- Staminodes
- there are no staminodes on the flower
- Stigma position
- the stigmas are positioned at the tip of the style
- Style length
- 0.25–1 mm
- Style petal-like
- the styles are not petal-like
- Style relative length
- NA
- Surface of ovary
- the ovary surface has no points, bumps or wrinkles
- 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 ribs
- NA
- Capsule splitting
- NA
- Carpel beak length
- 0 mm
- Fruit (pyxis) dehiscence
- NA
- Fruit beak length
- 0 mm
- Fruit cross-section
-
- NA
- the fruit is round in cross-section
- Fruit features (Brassicaceae)
- NA
- Fruit length
- 0 mm
- Fruit length relative to sepals
- NA
- Fruit length to width ratio
- 0
- Fruit locules
- NA
- Fruit shape
- NA
- Fruit stalk orientation
- the fruits point upward or spread or curve outward
- Fruit type (general)
-
- NA
- the fruit is dry but does not split open when ripe
- Fruit type (specific)
- NA
- Fruit width
- 0 mm
- Hair type on fruit
- NA
- Hairs on fruit
- NA
- 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 basal placentation, where one or a few ovules develop at the base of a simple or compound ovary
- Relative fruit length
- 0
- Rows of seeds in fruit (Brassicaceae)
- NA
- Schizocarpic fruit compression
- NA
- Schizocarpic fruit segments
- 0
- Seed length
- 5–8 mm
- Seed number
- 2
- Seed relative length
- the seed is about as long as it is wide
- Seed surface
-
- the seed is hairless
- the seed is smooth or without clear markings
- Seeds comose
- no hairs
- Septum in fruit (Brassicaceae)
- NA
- Wings on fruit
-
- NA
- the fruit does not have wings on it
- prickles on fruits
-
- NA
- 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 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
- Underground organs
- the plant has a rhizome (a horizontal underground stem with roots growing from it)
-
Leaves
- Bracteole edges
- the bracteole margins are entire (without teeth, lobes or hairs)
- Bracteole length
- 1–3 mm
- Bracteole number (Apiaceae)
- 0
- Bracteoles
- the plant has bracteoles between the primary bracts and the flowers
- Bracts in plantain (Plantago)
- NA
- Final leaf segment length (compound lvs only)
- 30–80 mm
- Final leaf segment length to width ratio (compound lvs only)
- 0.8–1.5
- Final leaf segment width (compound lvs only)
- 20–100 mm
- Floral bract texture
- NA
- Floral bracts
- the flower does not have bracts
- Flower bract length
- 0 mm
- Hairs on leaf stalk
- the petiole has no hairs on it
- 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
- no
- Inflated hairs on leaf
- the leaf blade does not have inflated hairs on it
- Leaf arrangement
- alternate: there is one leaf per node along the stem
- Leaf blade base
-
- the leaf has a distinct leaf stalk (petiole)
- 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
- the base of the leaf blade is rounded
- Leaf blade base symmetry
- the leaf blade base is symmetrical
- Leaf blade bloom
-
- the underside of the leaf has no noticeable bloom
- there is a noticeable powdery or waxy bloom on the underside of the leaf
- Leaf blade edges
-
- the edge of the leaf blade has lobes, or it has both teeth and lobes
- 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
- NA
- Leaf blade primary vein pattern
- the secondary veins branch off at intervals from the primary vein
- Leaf blade shape
- the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
- 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 of the leaf blade branch, but do not rejoin
- 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 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 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 leaf stalks
- the leaves have no leaf stalks, but attach directly to the stem
- 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)
- the leaf has a row of two or more lobes on each side of the central axis
- Leaf tip
- the tip of the leaf blade is acute (sharply pointed)
- Leaf tufts in axils
- there are no clusters of smaller leaves growing out of axils
- Leaf type
- the leaves are compound (made up of two or more discrete leaflets
- Leaf types
-
- NA
- 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
- At least 3
- Leaflet petiolules
- the leaflets of the compound leaf have petiolules
- Leaves per node
- there is one leaf 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, and each lobe itself has rows of lobes on each side of the lobe's central axis
- the leaf has lobes that themselves have lobes, and these secondary lobes also have lobes; there may be more than three levels of lobes
- Stipels
- there are no stipels at the bases of the petiolules
- 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
-
- forests
- river or stream floodplains
-
Stem, shoot, branch
- Branched tendrils
- NA
- Direction of stem hairs
- NA
- Flowering stem cross-section
- 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
- 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
- 20–90 cm
- Stem bloom
-
- the stem has a powdery or waxy film on it that can be rubbed away
- 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
Not classified
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.
- Maine
- unranked (S-rank: SNR)
- Massachusetts
- fairly widespread (S-rank: S4)
- Rhode Island
- extremely rare (S-rank: S1), state threatened (code: ST)
From Flora Novae Angliae dichotomous key
2. Caulophyllum thalictroides (L.) Michx. N
blue cohosh. CT, MA, ME, NH, RI, VT. Mesic, deciduous forests, often rich and rocky, high-terrace flood plain forests.
Native to North America?
Yes
Sometimes confused with
- Caulophyllum giganteum:
- flowers appearing before expansion of the leaves, mostly numbering 4-18 per inflorescence, and with purple to purple-brown sepals 6-9 mm long (vs. C. thalictroides, with flowers appearing with the leaves, mostly numbering 5-70 per inflorescence, and with usually yellow to yellow-green sepals 3-6 mm long).