- You are here:
 - Full Key
 - All other flowering non-woody plants
 - Daisies, goldenrods, and other aster family plants
 - Petasites hybridus
 
Petasites hybridus — butterbur sweet-coltsfoot
Copyright: various copyright holders. To reuse an image, please click it to see who you will need to contact.
Facts
Butterbur sweet-coltsfoot is native to Europe and an occasional visitor to North America. This distinctive wetland plant has unmistakable flowers as well as giant rhubarb-like leaves up to three feet across. Clinical trials have shown that extracts of butterbur root are effective in reducing frequency and severity of migraine.
Habitat
Anthropogenic (man-made or disturbed habitats), meadows and fields, shores of rivers or lakes
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
 - wetlands
 
 
- New England state
 - 
                                
                                    
- Connecticut
 - Massachusetts
 - Vermont
 
 
- Leaf type
 - leaves are simple (lobed or unlobed but not separated into leaflets)
 
- Leaf arrangement
 - the leaves are growing only at the base of the plant (basal)
 
- Leaf blade edges
 - the edge of the leaf blade has teeth
 
- Flower type in flower heads
 - the flower head has disk flowers only, and lacks the strap-shaped flowers
 
- Ray flower color
 - NA
 
- Tuft or plume on fruit
 - at least a part of the plume is made up of fine bristles
 
- Spines on plant
 - the plant has no spines
 
- Leaf blade length
 - 100–300 mm
 
- Disk flower number
 - 
                                
                                    
- 11-20
 - more than 50
 
 
- 
                        
Flowers
- Bract color
 - the bracts are colored, or at least tinged with, pink, red or purple
 
- Bract cycle number
 - 
                                
                                    
- there are two main cycles of bracts
 - there is one main cycle of bracts
 
 
- Bract keels
 - there is one distinct keel on the bracts
 
- Bract margins
 - there are few or no fine hairs along the bract margins
 
- Bract outer side hair type
 - the bracts are not hairy on their outer surface
 
- Bract outer side hairs
 - the bracts are not hairy on their outer surfaces
 
- Bract shape
 - 
                                
                                    
- the main bracts are oblanceolate (widest near the tip, but otherwise narrow and tapering)
 - the main bracts are oblong (roughly rectangular but rounded at the ends)
 
 
- Bract spines
 - the bracts have no spines
 
- Bract tip extension appearance
 - NA
 
- Bract tip extension edge
 - there are no projections from the bract tips
 
- Bract tip orientation
 - the bracts are pressed against the plant, or spreading out at the tips
 
- Bract tip shape
 - 
                                
                                    
- the tips of the bracts acute (have a sharp point)
 - the tips of the bracts are obtuse (have a blunt point)
 
 
- Bract width
 - 5–16
 
- Bracts
 - the bracts in separate cycles are similar or gradually changing from the outer to inner cycles
 
- Disk flower color
 - blue to purple
 
- Disk flower lobe number
 - 5
 
- Disk flower number
 - 
                                
                                    
- 11-20
 - more than 50
 
 
- Disk flower reproductive parts
 - the disk flower has either only pollen- or only seed-producing parts
 
- Disk flower shape
 - the disk flower is tube-shaped (cylindrical), or gradually widening like a funnel
 
- Flower head number
 - 
                                
                                    
- each flowering stem has four or more flower heads on it
 - each flowering stem has only one to three flower heads on it
 
 
- Flower head outer flowers
 - at the outer edge of the flower head, the flowers have no enlarged lobe or strap, and are of similar size as those in the center of the disk
 
- Flower head platform
 - the base has no bristles or papery scales
 
- Flower head platform surface
 - NA
 
- Flower head position
 - some or all the flower heads are grouped in clusters of two or more
 
- Flower head profile
 - 
                                
                                    
- the disk is flat or nearly flat across the top
 - the disk is rounded across the top
 
 
- Flower head shape
 - 
                                
                                    
- NA
 - the flower head is shaped like a cone with the point up
 
 
- Flower type in flower heads
 - the flower head has disk flowers only, and lacks the strap-shaped flowers
 
- Height of flower head base
 - 2.5–8.5 mm
 
- Inflorescence branching (Solidago)
 - NA
 
- Inflorescence shape
 - the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others
 
- Inflorescence stem
 - the stem of the inflorescence is not hairy
 
- Ovary cross-section
 - the ovary has five or more corners in cross-section
 
- Ovary hair type
 - the ovary has no hairs on it
 
- Ovary hairs
 - the ovary has no hairs on it
 
- Ovary lines or ribs
 - 
                                
                                    
- there are four to six lines or ribs visible on the ovary
 - there are seven to nine ribs visible on the ovary
 - there are ten or more ribs visible on the ovary
 
 
- Ovary profile
 - in profile, the ovary is very narrow
 
- Peduncle hair type
 - the hairs on the peduncles appear tangled or woolly
 
- Peduncle hairs
 - the peduncles are hairy
 
- Ray flower color
 - NA
 
- Ray flower reproductive parts
 - NA
 
- Ray flowers
 - 0
 
- Ray length
 - 0 mm
 
- Reproductive system
 - all the flowers on some plants have carpels, while all the flowers on other plants have stamens
 
- Scale tip
 - NA
 
- Smaller bracts at base of bracts
 - there is a cycle of much smaller bracts outside the cycle of larger and longer bracts
 
 - 
                        
Fruits or seeds
- Number of pappus parts
 - 1
 
- Ovary length in developed fruit
 - Up to 3 mm
 
- Seed hair tuft details
 - the pappus hairs are smooth and plain
 
- Seed hair tuft tips
 - the pappus hairs are slender
 
- Seed tuft scale number
 - 0
 
- Seed tuft type
 - the pappus is made of very fine hairs or bristles
 
- Top of disk flower ovary
 - NA
 
- Tuft or plume on fruit
 - at least a part of the plume is made up of fine bristles
 
 - 
                        
Glands or sap
- Sap
 - the sap is clear and watery
 
 - 
                        
Growth form
- Growth form
 - the plant has one or more free-standing stems
 
- Plant lifespan
 - the plant is perennial, it shows evidence of previous year's leaves, stems or stem bases
 
- 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
- Hairs on underside of leaf blade
 - the underside of the leaf is fuzzy or hairy
 
- Hairs on upper side of leaf blade
 - the upper side of the leaf is not hairy, or has very few hairs
 
- Leaf arrangement
 - the leaves are growing only at the base of the plant (basal)
 
- Leaf blade base
 - 
                                
                                    
- the leaf has a distinct petiole
 - the leaf has no petiole
 
 
- Leaf blade base shape
 - the base of the leaf is cordate (heart-shaped) or sagittate (arrow-shaped)
 
- Leaf blade bloom
 - the underside of the leaf has no noticeable bloom
 
- Leaf blade edges
 - the edge of the leaf blade has teeth
 
- Leaf blade hairs
 - the leaf blade has tangled or woolly-looking hairs
 
- Leaf blade length
 - 100–300 mm
 
- Leaf blade shape
 - 
                                
                                    
- NA
 - the leaf blade is cordate (heart-shaped with backward-facing rounded lobes), or sagittate (arrow-shaped with backward-facing pointed lobes)
 - the leaf blade is orbicular (roughly circular, as wide as long)
 
 
- Leaf blade surface colors
 - there is no noticeable color variation on the upper surface of the leaf
 
- Leaf blade tip
 - the tip of the leaf blade is rounded, with no point
 
- Leaf blade veins
 - NA
 
- Leaf blade width
 - 100–300 mm
 
- Leaf disposition
 - the lower leaves are larger, toothier, and/or on longer stalks than the upper leaves
 
- 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 tufts in axils
 - there are no clusters of smaller leaves
 
- Leaf type
 - leaves are simple (lobed or unlobed but not separated into leaflets)
 
- Leaflet number
 - 0
 
- Specific leaf type
 - the leaf has lobes that radiate from the base, somewhat like a hand
 
 - 
                        
Place
- Habitat
 - 
                                
                                    
- terrestrial
 - wetlands
 
 
- New England state
 - 
                                
                                    
- Connecticut
 - Massachusetts
 - Vermont
 
 
- Specific habitat
 - 
                                
                                    
- man-made or disturbed habitats
 - meadows or fields
 - shores of rivers or lakes
 
 
 - 
                        
Stem, shoot, branch
- Flowering stem cross-section
 - the flowering stem is circular, or with lots of small angles
 
- Leaves on stem
 - the flowering stem has no leaves above the base
 
- Stem internode hair direction
 - the hairs point mostly upwards to outwards
 
- Stem internode hair type
 - at least some of the hairs on the stem are tangled, matted or woolly
 
- Stem internode hairs
 - the stem has hairs between the nodes
 
 
Wetland status
Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)
In New England
Distribution
- Connecticut
 - present
 
- Maine
 - absent
 
- Massachusetts
 - present
 
- New Hampshire
 - absent
 
- Rhode Island
 - absent
 
- 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)
 
From Flora Novae Angliae dichotomous key
2. Petasites hybridus (L.) P.G. Gaertn., B. Mey., & Scherb. E
butterbur sweet-coltsfoot. Petasites officinalis Moench; P. vulgaris Hill • CT, MA, VT. Roadsides, fields, stream banks.