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- Symphyotrichum anticostense
Symphyotrichum anticostense — Anticosti American-aster
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Facts
You won't encounter Anticosti American-aster unless you are in a few sites in Canada, or on Maine's Aroostook River near the Canadian border. A globally imperiled species, it derives from a cross between New York American-aster (Symphyotrichum novi-belgii) and rush American-aster (S. boreale). Its greatest threats are river damming and invasive plants.
Habitat
Ridges or ledges, 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
- New England state
- Maine
- Leaf type
- leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
- Leaf arrangement
- 
                                
                                    - alternate: there is one leaf per node along the stem
- basal: the leaves are growing only at the base of the plant
 
- Leaf blade edges
- the edge of the leaf blade has teeth
- Flower type in flower heads
- the flower head has tubular disk flowers in the center and ray flowers, these often strap-shaped, around the periphery
- Ray flower color
- blue to purple
- 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
- 55–160 mm
- Disk flower number
- 
                                
                                    - 21-50
- more than 50
 
- 
                        Flowers- Bases of bract appendages
- NA
 - Bract color
- the bracts are not colored or tinged with pink, red or purple
 - Bract cycle number
- 
                                
                                    - there are three or more cycles of bracts
- there are two main cycles of bracts
 
 - Bract inner side hairs
- the bracts are not hairy on their inner surfaces
 - Bract margins
- there are 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 lanceolate (widest above the base, then taper narrowly towards the tip)
- the main bracts are linear (long and very narrow)
- 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)
- the main bracts are of a different shape than the given options
 
 - Bract spines
- the bracts have no spines
 - Bract texture
- 
                                
                                    - the bracts appear leathery or hardened
- the bracts have a similar texture to a leaf
 
 - Bract tip color
- the tips are a different color from the center of the bract
 - 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 acuminate (tapered to a narrow point)
 
 - Bract width
- 1.5–2
 - Bracts
- the bracts in separate cycles are similar or gradually changing from the outer to inner cycles
 - Disk flower color
- 
                                
                                    - blue to purple
- yellow
 
 - Disk flower lobe number
- 5
 - Disk flower number
- 
                                
                                    - 21-50
- more than 50
 
 - Disk flower reproductive parts
- the disk flower has both pollen- and seed-producing parts
 - Disk flower shape
- 
                                
                                    - the disk flower is abruptly widened at some point below the lobes
- 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
 - Flower head outer flowers
- at the outer edge of the flower head, each flower has a single enlarged lobe or strap
 - Flower head platform
- the base has no bristles or papery scales
 - Flower head platform surface
- NA
 - Flower head position
- 
                                
                                    - each of the flower heads is separate on its own peduncle (stalk), not clustered in groups
- 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
- the sides of the flower head are roughly parallel, like a cylinder
 - Flower type in flower heads
- the flower head has tubular disk flowers in the center and ray flowers, these often strap-shaped, around the periphery
 - Height of flower head base
- 6–10 mm
 - Inflorescence branching (Solidago)
- NA
 - Inflorescence shape
- the inflorescence is not flat-topped but appears rounded, with some flower heads distinctly higher than others
 - Ovary cross-section
- the ovary is compressed (flattened)
 - Ovary hair type
- the ovary has hairs on it, but the hairs have no glands
 - Ovary hairs
- the ovary has hairs on it
 - Ovary lines or ribs
- there are four to six lines or ribs visible on the ovary
 - Ovary profile
- in profile, the ovary is roughly egg-shaped, but widest above the middle
 - Peduncle hair type
- the hairs on the peduncles are simple (not branched), don’t have glands, and are not woolly
 - Peduncle hairs
- the peduncles are hairy
 - Peduncle length
- 8–57 mm
 - Ray flower color
- blue to purple
 - Ray flower reproductive parts
- the ray flowers have carpels or stamens, but not both
 - Ray flowers
- 26-50
 - Ray length
- 9.5–20 mm
 - Reproductive system
- some of the flowers on the plant have only carpels or stamens, while others have both carpels and 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
 - Style branch number
- the style has two branches
 - Style branches
- the style branch is narrow at the tip, or the style branches are narrow at the tips
 
- 
                        Fruits or seeds- Number of pappus parts
- 11 or more
 - Ovary length in developed fruit
- 1.5–2.8 mm
 - Seed hair tuft color
- the pappus hairs are another color
 - Seed hair tuft details
- the pappus hairs are hooked or barbed
 - Seed hair tuft length
- 7–8 mm
 - Seed hair tuft tips
- the pappus hairs are slender
 - Seed hairs uniform
- all the pappus hairs are approximately the same length
 - 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- Final leaf segment length (compound lvs only)
- 0 mm
 - Final leaf segment width (compound lvs only)
- 0 mm
 - Hairs on underside of leaf blade
- 
                                
                                    - the underside of the leaf is fuzzy or hairy
- the underside of the leaf is not hairy, or has very few hairs
 
 - Hairs on upper side of leaf blade
- the upper side of the leaf is not hairy, or has very few hairs
 - Leaf arrangement
- 
                                
                                    - alternate: there is one leaf per node along the stem
- basal: the leaves are growing only at the base of the plant
 
 - Leaf blade base
- 
                                
                                    - the leaf has a distinct petiole
- the leaf has no petiole and at the base it clasps the stem, or goes all the way around the stem so the stem appears to pierce the leaf
 
 - 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 edges
- the edge of the leaf blade has teeth
 - Leaf blade flatness
- the edges of the leaf are curled under
 - Leaf blade hairs
- 
                                
                                    - NA
- the leaf blade has simple hairs with no glands, and not tangled or wooly
 
 - Leaf blade length
- 55–160 mm
 - Leaf blade shape
- 
                                
                                    - the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- the leaf blade is oblanceolate (lance-shaped, but with the widest point above the middle of the leaf blade)
 
 - 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 acuminate (tapers to a long, thin point)
- the tip of the leaf blade is acute (sharply pointed)
 
 - Leaf blade width
- 5–25 mm
 - Leaf disposition
- the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
 - Leaf spines
- there are no spines on the leaf edges
 - Leaf stalk
- the leaves have leaf stalks
 - Leaf tip extension
- NA
 - Leaf type
- leaves are simple (i.e., lobed or unlobed but not separated into leaflets)
 - Leaflet number
- 0
 - Specific leaf type
- the leaves are simple (i.e., lobed or unlobed but not separated into leaflets
 
- 
                        Place- Habitat
- terrestrial
 - New England state
- Maine
 - Specific habitat
- 
                                
                                    - ridges or ledges
- shores of rivers or lakes
 
 
- 
                        Stem, shoot, branch- Leaves on stem
- there is at least one full leaf above the base of the flowering stem
 - Stem internode hair direction
- the hairs point mostly upwards to outwards
 - Stem internode hair type
- 
                                
                                    - the hairs on the stem are plain, without glands or branches, and not tangled
- the stem has no hairs between the nodes
 
 - Stem internode hairs
- 
                                
                                    - the stem has hairs between the nodes
- the stem has no hairs between the nodes
 
 
Wetland status
Not classified
In New England
Distribution
- Connecticut
- absent
- Maine
- present
- Massachusetts
- absent
- 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.
- Maine
- extremely rare (S-rank: S1), endangered (code: E)
From Flora Novae Angliae dichotomous key
1. Symphyotrichum anticostense (Fern.) Nesom NC
Anticosti American-aster. Aster anticostensis Fern. • ME; northern portion of state. Ice-scoured river shores and adjacent, disintegrating ledges.
Native to North America?
Yes
Sometimes confused with
- Symphyotrichum boreale:
- leaf blades linear to oblong-linear, often with revolute margins, mostly 2–5 mm wide, base of stem thinner than 2.5 mm, and plants mostly of high-pH fens (vs. S. anticostense, with leaf blades usually narrow-lanceolate , with plane margins, 5–25 mm wide, base of stem thicker than 2.5 mm, and plants mostly of river shores).
- Symphyotrichum novi-belgii:
- leaf blades narrow-lanceolate to oblanceolate, narrowing to the base, flat, herbaceous to fleshy, and most peduncles shorter than 3 cm (vs. leaf blades tending to be narrow-lanceolate, scarcely narrowing to the base, folded along the midrib, coriaceous, and many peduncles longer than 3 cm).
Synonyms
- Aster anticostensis Fern.
 
                         
                         
                        ![Plant form: Symphyotrichum anticostense. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-239x239/Asteraceae/symphyotrichum-anticostense-ha-ahaines-e.jpg) 
                        ![Leaves: Symphyotrichum anticostense. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-239x239/Asteraceae/symphyotrichum-anticostense-le-ahaines-d.jpg) 
                         
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