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- Astragalus
- Astragalus alpinus
Astragalus alpinus — alpine milk-vetch
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Facts
Alpine milk-vetch has a circumboreal distribution, and is found across northern North America. In New England it is rare and occurs in Maine, New Hampshire and Vermont on open river shores on high-pH, rocky or gravel substrate.
Habitat
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
- wetlands
- Flower petal color
- 
                                
                                    - blue to purple
- white
 
- 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 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
- there are four 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
- 10
- Fruit type (general)
- the fruit is dry and splits open when ripe
- Fruit length
- 8–16 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 opening
- the anthers have narrow slits or furrows that run lengthwise along the anthers
 - Anther spurs
- the anthers do not have spurs on them
 - Calyx symmetry
- there is only one way to evenly divide the calyx (the calyx is bilaterally symmetrical)
 - Carpels fused
- 
                                
                                    - NA
- the carpel is solitary or (if 2 or more) the carpels are not fused to one another
 
 - 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 surface
- the filament is smooth, with no hairs or scales
 - Flower description
- the flower has a superior ovary and a hypanthium
 - Flower length
- 7–13 mm
 - Flower number
- 5–15
 - Flower orientation
- the flower points upwards or is angled outwards
 - Flower petal color
- 
                                
                                    - blue to purple
- 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
 - Fused stamen clusters
- there are two clusters of fused stamens
 - Fusion of sepals and petals
- the petals or the sepals are fused into a cup or tube
 - Hairs on inflorescence
- the axis of the inflorescence has hairs entirely without glands
 - Horns in hoods (Asclepias)
- NA
 - Hypanthium
- the flower has a hypanthium
 - 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 flower stalk
- 0.5–1.5 mm
 - Length of peduncle
- 30–150 mm
 - Marks on petals
- the petals have spots or streaks on them
 - Nectar spur
- the flower has no nectar spurs
 - Number of carpels
- 1
 - Number of pistils
- 1
 - Number of sepals, petals or tepals
- 
                                
                                    - there are five petals, sepals, or tepals in the flower
- there are four 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
 - Petal and sepal arrangement
- the flower includes two cycles of petal- or sepal-like structures
 - Petal and sepal colors
- 
                                
                                    - blue to purple
- white
 
 - 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)
- the petals in bud meet exactly at the margins without overlapping (valvate)
 
 - Petal folds or pleats
- 
                                
                                    - the petals of the flower do not have folds or plaits
- the petals of the flower have folds or plaits on them
 
 - Petal hairs (Viola)
- NA
 - Petal length
- 7–13 mm
 - Petal length relative to sepals
- the petals are longer than the sepals
 - Petal number
- 5
 - Petal shape
- the petal outline is elliptic (shaped like an ellipse; widest near the middle and tapering at both ends)
 - Petal tip shape
- the petal tip is retuse (with a blunt or rounded apex and a notch at the center)
 - Petal tips (Cuscuta)
- NA
 - Petal width
- 3–7.5 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
 - Sepal appendages
- the sepals do not have appendages on them
 - Sepal appendages (Oenothera)
- NA
 - Sepal auricles
- the sepals have no auricles
 - Sepal color
- green to brown
 - Sepal length
- 4–6 mm
 - Sepal number
- 4–5
 - 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
 - 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 acute (is sharply pointed)
 - Sepal uniformity
- one or more of the sepals is much narrower or shorter than the others
 - Sepals fused only to sepals
- the sepals are fused to each other (not other flower parts), at least near their bases
 - Stamen number
- 10
 - Stamens fused
- the stamens are attached to one another at or near their bases
 - Staminodes
- there are no staminodes on the flower
 - Stigma position
- the stigmas are positioned at the tip of the style
 - Style petal-like
- the styles are not petal-like
 - 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
- the capsule splits by two main valves, teeth or pores
 
 - Fruit (pyxis) dehiscence
- NA
 - Fruit cross-section
- the fruit is roughly triangular in cross-section
 - Fruit features (Brassicaceae)
- NA
 - Fruit length
- 8–16 mm
 - Fruit length relative to sepals
- the fruit is longer than its associated sepals
 - Fruit locules
- one
 - Fruit shape
- 
                                
                                    - the fruit is ellipsoid (widest in the middle and tapering to each end)
- the fruit is obloid (longer than wide and with rounded ends)
 
 - Fruit stalk orientation
- 
                                
                                    - the fruits curve or droop downwards
- 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 legume (a fruit that splits into two valves, but only has a single carpel; think of a pea pod)
 - Fruit width
- 3–4 mm
 - 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 have hairs on them
 - Legumes (Fabaceae)
- the legume has none of the mentioned special features
 - Mericarp length
- 0 mm
 - Mericarp segment shape (Desmodium)
- NA
 - Other markings on berry
- NA
 - Ovary stipe
- the ovary or fruit has a stipe
 - Ovary stipe length
- 1.5–3.5 mm
 - Placenta arrangement
- the plant has parietal placentation, where ovules develop on the wall or slight outgrowths of the wall forming broken partitions within a compound ovary
 - Rows of seeds in fruit (Brassicaceae)
- NA
 - Schizocarpic fruit compression
- NA
 - Schizocarpic fruit segments
- 0
 - Seed length
- 2.5–3 mm
 - Seed number
- 5–10
 - Seed relative length
- the seed is longer than it is wide
 - Seed surface
- the seed is smooth or without clear markings
 - 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)
 - 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
- there are spines on the plant
 - Underground organs
- the plant has a caudex (the root mass is firm and hardened at the top)
 
- 
                        Leaves- 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 to width ratio (compound lvs only)
- 1.3–3.5
 - Floral bracts
- the flower has one or more bracts associated with it
 - Flower bract length
- 0.5–2 mm
 - Hairs on leaf stalk
- the petiole has hairs on it
 - Hairs on underside of leaf
- the underside of the leaf is fuzzy or hairy
 - Hairs on upper side of leaf
- 
                                
                                    - the upper side of the leaf is fuzzy or hairy
- 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 no stalk
 - Leaf blade base shape
- the base of the leaf blade is rounded
 - Leaf blade base symmetry
- the leaf blade base is symmetrical
 - 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
- 20–80 mm
 - Leaf blade primary vein pattern
- the secondary veins branch off at intervals from the primary vein
 - Leaf blade shape
- the leaf blade is elliptic (widest near the middle and tapering at both ends)
 - 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 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
- 2–7 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
- NA
 - 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
 - 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 stalk length
- 30–120 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 retuse (blunt or rounded, with a notch at the tip)
- the tip of the leaf blade is rounded, with no point
 
 - Leaf type
- the leaves are compound (made up of two or more discrete leaflets
 - Leaf variation
- the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
 - Leaflet number
- 15–25
 - Leaflet petiolules
- the leaflets of the compound leaf lack 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
 - Stipels
- there are no stipels at the bases of the petiolules
 - Stipule features
- NA
 - Stipule fused to leaf stalk
- the stipules are fused to the petioles for some or most of their length
 - Stipule length
- 1.5–6 mm
 - Stipules
- the plant has stipules
 
- 
                        Place- Habitat
- wetlands
 - Specific habitat
- shores of rivers or lakes
 
- 
                        Stem, shoot, branch- Branched tendrils
- NA
 - Direction of stem hairs
- NA
 - 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
 - Plant height
- 0.5–10 cm
 - Stem bloom
- there is no powdery or waxy film on the stem
 - Stem hair distribution
- NA
 - Stem orientation
- 
                                
                                    - the stems are upright or angled outwards
- the stems trail at the base, but may turn upwards at the tips
 
 - Stem roughness between nodes
- the stem does not feel rough
 - Stem spacing
- the plant is growing in tufts, or compact clusters with closely spaced stems, or it is densely matted together in clumps, cushionlike
 - Tendril origin
- NA
 - Tendrils
- the plant does not have tendrils
 - Wings on stem
- the stem does not have wings on it
 
Wetland status
Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)
In New England
Distribution
- Connecticut
- absent
- Maine
- present
- Massachusetts
- absent
- New Hampshire
- present
- Rhode Island
- absent
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Maine
- uncommon (S-rank: S3), special concern (code: SC)
var. brunetianus
- New Hampshire
- extirpated (S-rank: SX), -- (code: --)
- Vermont
- extirpated (S-rank: SX)
From Flora Novae Angliae dichotomous key
1. Astragalus alpinus L. var. brunetianus Fern. NC
alpine milk-vetch. Astragalus alpinus L. var. labradoricus (DC.) Fern. • ME, NH, VT. Open, gravel, cobble, and ledge river shores in regions of high-pH bedrock and/or till.
Native to North America?
Yes
Sometimes confused with
Synonyms
- Astragalus alpinus L. var. labradoricus (DC.) Fern.
 
                        ![Flowers: Astragalus alpinus. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-239x239/Fabaceae/astragalus-alpinus-fl-ahaines-c.jpg) 
                        ![Fruits: Astragalus alpinus. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-239x239/Fabaceae/astragalus-alpinus-fr-ahaines.jpg) 
                         
                        ![Flowers: Astragalus alpinus. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-239x239/Fabaceae/astragalus-alpinus-fl-ahaines-b.jpg) 
                        ![Leaves: Astragalus alpinus. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-239x239/Fabaceae/astragalus-alpinus-le-ahaines-e.jpg) 
                        ![Plant form: Astragalus alpinus. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-239x239/Fabaceae/astragalus-alpinus-ha-ahaines-a.jpg) 
                        ![Flowers: Astragalus alpinus. ~ By Louis-M. Landry. ~ Copyright © 2025 Louis-M. Landry. ~ LM.Landry[at]videotron.ca  ~ CalPhotos - calphotos.berkeley.edu/flora/](https://newfs.s3.amazonaws.com/taxon-images-239x239/Fabaceae/astragalus-alpinus-fl-llandry.jpg) 
                        ![Leaves: Astragalus alpinus. ~ By Arthur Haines. ~ Copyright © 2025 Arthur Haines. ~ arthur.d.haines[at]gmail.com](https://newfs.s3.amazonaws.com/taxon-images-239x239/Fabaceae/astragalus-alpinus-le-ahaines-f.jpg) 
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