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- Astragalus robbinsii
Astragalus robbinsii — Robbins' milk-vetch
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Facts
Robbins' milk-vetch has a disjunct distribution in North America, with separate western and northeastern ranges. There are three varieties in New England that differ in range and conservation status. One of them (Astragalus robbinsii var. robbinsii) is now extinct. Another (A. robbinsii var. jesupii) is found only in three sites along the Connecticut River in New Hampshire and Vermont, on ice-scoured shores. The third (A. robbinsii var. minor) is found in Maine and Vermont.
Habitat
Cliffs, balds, or ledges, 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
- 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
- Fruit type (general)
- the fruit is dry and splits open when ripe
- Fruit length
- 13–25 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
- 17–22 mm
- Flower number
- At least 5
- 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
- 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 length
- 20–30 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 flower stalk
- 1.5–5 mm
- 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
- 7–12 mm
- Petal number
- 5
- Petal tip shape
-
- the petal tip is acute (sharply pointed)
- the petal tip is obtuse (bluntly pointed)
- Petal tips (Cuscuta)
- NA
- 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 color
- green to brown
- Sepal length
- 3.5–7.5 mm
- Sepal number
- 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 subulate (narrowly tapering from the base to the apex; awl-shaped)
- Sepal texture
- NA
- Sepal tip shape
- the sepal tip is acuminate (tapers to a very narrow point)
- 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
- 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 beak length
- 0.5–3 mm
- Fruit cross-section
- the fruit is roughly triangular in cross-section
- Fruit features (Brassicaceae)
- NA
- Fruit length
- 13–25 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)
- the fruit is spherical
- 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
- 3.5–5.5 mm
- 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 does not have a stipe
- the ovary or fruit has a stipe
- Ovary stipe length
- 0.5–5 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 number
- 3–11
- 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
- the plant has no spines
- Underground organs
-
- the plant has a caudex (the root mass is firm and hardened at the top)
- there is a thickened taproot on the plant
-
Leaves
- Bracteole number (Apiaceae)
- 0
- Bracteoles
-
- the plant has bracteoles between the primary bracts and the flowers
- there are no bracteoles on the plant
- Bracts in plantain (Plantago)
- NA
- Final leaf segment length (compound lvs only)
- 5–20 mm
- Final leaf segment length to width ratio (compound lvs only)
- 1.3–3.5
- Floral bracts
-
- the flower does not have bracts
- the flower has one or more bracts associated with it
- Hairs on underside of leaf
-
- the underside of the leaf is fuzzy or hairy
- 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
- 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 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 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)
- the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both ends)
- the leaf blade is oblong (rectangular but with rounded ends)
- the leaf blade is ovate (widest below the middle and broadly 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 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
- the hairs are flat against the leaf surface, mostly pointing towards the leaf tip
- 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 stalk length
- 0–90 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 obtuse (bluntly pointed)
- the tip of the leaf blade is retuse (blunt or rounded, with a notch at the tip)
- 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
- 7–17
- 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
- the stipules are not fused to the petioles
- Stipules
- the plant has stipules
- Teeth per side of leaf blade
- 0
-
Place
- Habitat
-
- terrestrial
- wetlands
- Specific habitat
-
- cliffs, balds, or ledges
- ridges or ledges
- shores of rivers or lakes
-
Stem, shoot, branch
- Branched tendrils
- NA
- Hair between stem nodes
-
- the stem has hairs between the nodes
- the stem has no hairs between the nodes
- Hairs between stem nodes
-
- the hairs on the stem are plain, without glands or branches, and not tangled
- the stem has no hairs between the nodes
- Leaves on stem
- there is at least one full leaf above the base of the flowering stem
- Plant height
- 10–50 cm
- Stem orientation
- the stems are upright or angled outwards
- 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
Wetland status
Occurs only in non-wetlands. (Wetland indicator code: UPL)
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
- extremely rare (S-rank: S1)
var. jesupii
- New Hampshire
- extremely rare (S-rank: S1), endangered (code: E)
- Vermont
- extremely rare (S-rank: S1), endangered (code: E)
var. minor
- Maine
- extremely rare (S-rank: S1), endangered (code: E)
- Vermont
- rare (S-rank: S2)
var. robbinsii
- Vermont
- extirpated (S-rank: SX)
Subspecies and varieties
Variety robbinsii is known from VT. It is now extinct. Variety jesupii is known from NH, VT. Variety minor is known from ME, VT. All the infraspecific taxa are of regional conservation concern.
From Flora Novae Angliae dichotomous key
6. Astragalus robbinsii (Oakes) Gray NC
Robbin’s milk-vetch. 6a. Phaca robbinsii Oakes; 6b. Astragalus jesupii (Egglest. & Sheldon) Britt.; 6c. Astragalus blakei Egglest.; A. robbinsii (Oakes) Gray var. blakei (Egglest.) Barneby • ME, NH, VT. River shore beaches and ledges, cliffs, and talus in regions of high-pH bedrock and/or till.
1a. Flowers 7–9 (–10) mm long, usually with a white corolla; legume 10–15 mm long; plants historically documented from a single station on the Winooski River in vt
… 6a. A. robbinsii var. robbinsii
1b. Flowers 10–12 mm long, usually with a light purple corolla; legume 15–25 mm long; plants not known from the Winooski River, vt
2a. Legume tipped by a beak 1.5–3 mm long; leaflets glabrous or nearly so abaxially; plants known from the Connecticut River in NH and VT … 6b. A. robbinsii var. jesupii Egglest. & Sheldon
2b. Legume scarcely beaked or with a projection up to 1.5 mm long; leaflets strigose abaxially; plants known from the mountains of northern vt and river shores and ledges of northern and western ME … 6c. A. robbinsii var. minor (Hook.) Barneby
Variety robbinsii is known from VT. It is now extinct. Variety jesupii is known from NH, VT. Variety minor is known from ME, VT. All the infraspecific taxa are of regional conservation concern.
Native to North America?
Yes
Sometimes confused with
- Astragalus alpinus:
- principal leaves with 15-25 leaflets, keel petal not or only slightly shorter than the banner petal, and upper suture of fruit prominently sulcate (vs. A. robbinsii, with the principal leaves with mostly 7-15 leaflets, keel petal markedly shorter than the banner petal, and upper suture of fruit scarcely sulcate).
- Astragalus eucosmus:
- legumes mostly 8-11 mm long, +/- sessile, and flowers 6-9 mm long (vs. A. robbinsii, with legumes legumes 13-25 mm long, on a stipe 2-5 mm long, and flowers mostly 10-12 mm long).
Synonyms
- Phaca robbinsii Oakes