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- Lotus unifoliatus
Lotus unifoliatus — American bird's-foot-trefoil
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Facts
American bird's-foot-trefoil is native to western and central North America and introduced to some eastern states, including Connecticut and Massachusetts. The flowers are solitary and borne on peduncles arising from the leaf axils.
Habitat
Anthropogenic (man-made or disturbed habitats)
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
- Flower petal color
-
- pink to red
- white
- yellow
- 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
-
- both the petals and sepals are separate and not fused
- 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
- 15–30 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 are two or more ways to evenly divide the calyx (the calyx is radially 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 number
- 1
- Flower petal color
-
- pink to red
- white
- yellow
- 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 knob-like at the tip, and unbranched
- Fused stamen clusters
- there are two clusters of fused stamens
- Fusion of sepals and petals
-
- both the petals and sepals are separate and not fused
- the petals or the sepals are fused into a cup or tube
- Hairs on flower stalk
-
- the flower stalk has hairs on it
- the flower stalk has no hairs on it
- Hairs on inflorescence
-
- the axis of the inflorescence has hairs entirely without glands
- the axis of the inflorescence has no hairs on it
- 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 peduncle
- 3–15 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
-
- pink to red
- white
- yellow
- 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)
- 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
- 4–9 mm
- Petal number
- 5
- Petal shape
- the petal outline is obovate (roughly egg-shaped, but with the widest point above the middle of the leaf blade)
- 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 number
- 5
- Sepal orientation
- the sepals are slightly curved outwards from the corolla
- Sepal relative length
- the sepal lobes are longer than the fused portion
- Sepal uniformity
-
- all the sepals are about the same size
- 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 lengths differ
- the stamens are all approximately the same length
- 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 at least somewhat flattened
- Fruit features (Brassicaceae)
- NA
- Fruit length
- 15–30 mm
- Fruit length relative to sepals
- the fruit is longer than its associated sepals
- Fruit locules
- one
- Fruit shape
- 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)
- Hairs on fruit
-
- the fruits are not hairy
- 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
- 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
- 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 only a single year or less
- Parasitism
- the plant is not parasitic
- Plant color
- the leaves or young stems of the plant are green
- Spines on plant
- the plant has no spines
-
Leaves
- Bracteole number (Apiaceae)
- 0
- Bracteole shape
- NA
- 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)
- 5–25 mm
- Final leaf segment length to width ratio (compound lvs only)
- 2–5
- Floral bracts
- the flower has one or more bracts associated with it
- Flower bract length
- 5–8 mm
- Hairs on leaf stalk
-
- the petiole has hairs on it
- the petiole has no hairs on 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 fuzzy or hairy
- the upper side of the leaf is not hairy, or it has very few hairs
- 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 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 primary vein pattern
- the secondary veins branch off at intervals from the primary vein
- Leaf blade shape
-
- the leaf blade is lanceolate (lance-shaped; widest below the middle and tapering at both 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 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 length
- At least 0 mm
- Leaf teeth and lobes
- the edge of the leaf blade is entire (has no teeth or lobes)
- 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
- 1–3
- Leaflet petiolules
- the leaflets of the compound leaf have 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 shape
- the stipules are linear (very narrow with more or less parallel sides)
- Stipules
- the plant has stipules
- Teeth per side of leaf blade
- 0
-
Place
- Habitat
- terrestrial
- Specific habitat
- man-made or disturbed habitats
-
Scent
- Plant odor
- the plant does not have much of a smell
-
Stem, shoot, branch
- Branched tendrils
- NA
- Flowering stem cross-section
- the flowering stem is circular, or with lots of small angles so that it is roughly circular
- 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
- Leaves on stem
- there is at least one full leaf above the base of the flowering stem
- Plant height
- 20–60 cm
- Stem orientation
- the stems are upright or angled outwards
- Tendril origin
- NA
- Tendrils
- the plant does not have tendrils
Wetland status
Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)
In New England
Distribution
- Connecticut
- present
- Maine
- absent
- Massachusetts
- present
- 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.
var. unifoliatus
- Massachusetts
- not applicable (S-rank: SNA)
Subspecies and varieties
Our variety is Lotus unifoliatus (Hook.) Benth. var. unifoliatus.
From Flora Novae Angliae dichotomous key
2. Lotus unifoliatus (Hook.) Benth. var. unifoliatus E
American bird’s-foot-treefoil. Acmispon americanum (Nutt.) Rydb.; Hosackia americana (Nutt.) Piper; Lotus americanus (Nutt.) Bisch.; L. purshianus F.E. & E.G. Clem. ex Ottley; L. purshianus F.E. & E.G. Clem. ex Ottley var. glaber (Nutt.) Munz • CT, MA. Waste areas, yards.
Native to North America?
Yes and no (some introduced)
Synonyms
- Acmispon americanum (Nutt.) Rydb.
- Hosackia americana (Nutt.) Piper
- Lotus americanus (Nutt.) Bisch.
- Lotus purshianus F.E. & E.G. Clem. ex Ottley
- Lotus purshianus F.E. & E.G. Clem. ex Ottley var. glaber (Nutt.) Munz