• You are here:
• Simple Key
• All other flowering non-woody plants
• All other herbaceous, flowering dicots
• Caulophyllum thalictroides

Caulophyllum thalictroides — blue cohosh

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

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 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

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae