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- 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)
var. brunetianus
- Maine
- uncommon (S-rank: S3), special concern (code: SC)
- New Hampshire
- extirpated (S-rank: SX), X (code: X)
- Vermont
- extirpated (S-rank: SX)
Subspecies and varieties
Our variety is Astragalus alpinus L. var. brunetianus Fern.
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
- Astragalus eucosmus:
- principal leaves with mostly 7-15 leaflets, keel petal markedly shorter than the banner petal, and upper suture of fruit scarcely sulcate (vs. A. alpinus, with principal leaves with 15-25 leaflets, keel petal not or only slightly shorter than the banner petal, and upper suture of fruit prominently sulcate).
- Astragalus robbinsii:
- principal leaves with mostly 7-15 leaflets, keel petal markedly shorter than the banner petal, and upper suture of fruit scarcely sulcate (vs. A. alpinus, with principal leaves with 15-25 leaflets, keel petal not or only slightly shorter than the banner petal, and upper suture of fruit prominently sulcate).
Synonyms
- Astragalus alpinus L. var. labradoricus (DC.) Fern.