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- Trifolium
- Trifolium dubium
Trifolium dubium — lesser hop clover
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Facts
Lesser hop clover is a widely introduced annual legume used as forage. It may invade lawns, where it can tolerate mowing.
Habitat
Anthropogenic (human-disturbed or -maintained habitats), meadows and fields
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
- 
                                
                                    - Connecticut
- Maine
- Massachusetts
- Rhode Island
- Vermont
 
- Flower petal color
- 
                                
                                    - green to brown
- 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 has teeth
- 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
- Stamen number
- 10
- Fruit type (general)
- the fruit is dry but does not split open when ripe
- Fruit length
- 1.5–2 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
- 2.5–3.5 mm
 - Flower number
- 3–25
 - Flower petal color
- 
                                
                                    - green to brown
- 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
 - 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
 - Hairs on flower stalk
- the flower stalk has hairs on it
 - 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
- 8–9 mm
 - Inflorescence one-sided
- the flowers are arrayed in a spiral around the inflorescence axis or branches, or occur singly, or in several ranks
 - Inflorescence width
- Up to 8 mm
 - Inner tepals (Rumex)
- NA
 - Length of flower stalk
- 0.2–0.5 mm
 - Length of peduncle
- 5–40 mm
 - Marks on petals
- there are no noticeable marks on the petals
 - Nectar spur
- the flower has no nectar spurs
 - Number of branches in umbel
- 0
 - 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
 - Perianth shape
- NA
 - Petal and sepal arrangement
- the flower includes two cycles of petal- or sepal-like structures
 - Petal and sepal colors
- 
                                
                                    - green to brown
- yellow
 
 - Petal appearance
- the petals are thin and delicate, and pigmented (colored other than green or brown)
 - Petal base
- the petal narrows gradually or does not narrow at the base
 - 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
- 3–3.5 mm
 - Petal length relative to sepals
- the petals are longer than the sepals
 - Petal number
- 5
 - 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
- 2 mm
 - Sepal number
- 5
 - Sepal relative length
- the sepal lobes are approximately the same length as the fused portion
 - Sepal shape
- 
                                
                                    - the sepal outline is linear (extremely narrow, thread-like)
- the sepal outline is roughly triangular
 
 - 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
 - Spur length
- 0 mm
 - Spur number
- NA
 - Stamen attachment
- the stamens are attached at or near the bases of the petals or tepals
 - Stamen morphology
- the stamens within each cycle are the same
 - 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
 - Style length
- 0.4 mm
 - 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
 
 - Carpel beak length
- 0 mm
 - Fruit (pyxis) dehiscence
- NA
 - Fruit features (Brassicaceae)
- NA
 - Fruit length
- 1.5–2 mm
 - Fruit length relative to sepals
- the fruit is longer than its associated sepals
 - Fruit locules
- one
 - Fruit stalk orientation
- the fruits curve or droop downwards
 - Fruit type (general)
- the fruit is dry but does not split 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)
 - 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
- 0.8–1 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
- 1 mm
 - Seed number
- 1
 - Seed relative length
- the seed is about as long as it is wide
 - 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
 - Plants darken when dry
- no
 - Spines on plant
- the plant has no spines
 
- 
                        Leaves- Bracteole number (Apiaceae)
- 0
 - Bracts in plantain (Plantago)
- NA
 - Final leaf segment length (compound lvs only)
- 5–12 mm
 - Final leaf segment length to width ratio (compound lvs only)
- 1.3–2
 - Final leaf segment width (compound lvs only)
- 3–8 mm
 - 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 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
 - 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 a distinct leaf stalk (petiole)
 - 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
 - Leaf blade base symmetry
- the leaf blade base is symmetrical
 - Leaf blade bloom
- the underside of the leaf has no noticeable bloom
 - Leaf blade edges
- 
                                
                                    - the edge of the leaf blade has teeth
- 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
- NA
 - Leaf blade primary vein pattern
- the secondary veins branch off at intervals from the primary vein
 - Leaf blade shape
- 
                                
                                    - the leaf blade is cordate (heart-shaped with backward-facing rounded lobes), or sagittate (arrow-shaped with backward-facing pointed lobes)
- the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
 
 - 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 vein pattern
- the major veins of the leaf blade branch, but do not rejoin
 - 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
- 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 length
- 8–12 mm
 - Leaf teeth and lobes
- 
                                
                                    - the edge of the leaf blade is entire (has no teeth or lobes)
- the leaf blade margin has forward-pointing teeth
 
 - Leaf 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 types
- NA
 - Leaf variation
- the leaves are nearly similar in size, prominence of teeth, and length of stalks throughout the stem
 - Leaflet number
- 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
 - Stipule edges
- the stipule margins have teeth on them
 - Stipule features
- NA
 - Stipule fused to leaf stalk
- the stipules are fused to the petioles for some or most of their length
 - Stipule length
- 4–5 mm
 - Stipule shape
- the stipules are ovate (widest below the middle and broadly tapering at both ends)
 - Stipules
- the plant has stipules
 
- 
                        Place- Habitat
- terrestrial
 - New England state
- 
                                
                                    - Connecticut
- Maine
- Massachusetts
- Rhode Island
- Vermont
 
 - Specific habitat
- 
                                
                                    - human-disturbed or -maintained habitats
- meadows or fields
 
 
- 
                        Scent- Plant odor
- the plant does not have much of a smell
 
- 
                        Stem, shoot, branch- Branched tendrils
- NA
 - Direction of stem hairs
- the hairs point mostly upwards to outwards
 - 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
 
 - 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
- 5–40 cm
 - Stem bloom
- there is no powdery or waxy film on the stem
 - Stem hair distribution
- the hairs on the stem are distributed more of less uniformly
 - Stem nodes swollen
- the stem is not swollen at the nodes
 - Stem orientation
- the stems are upright or angled outwards
 - Stem roughness between nodes
- the stem does not feel rough
 - Stem succulence
- the stems are not succulent
 - Tendril origin
- NA
 - Tendrils
- the plant does not have tendrils
 - Wings on stem
- the stem does not have wings on it
 
Wetland status
Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)
In New England
Distribution
- Connecticut
- present
- Maine
- present
- Massachusetts
- present
- New Hampshire
- absent
- Rhode Island
- present
- Vermont
- present
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
- not applicable (S-rank: SNA)
From Flora Novae Angliae dichotomous key
6. Trifolium dubium Sibthorp E
lesser hop clover. CT, MA, ME, RI, VT. Fields, roadsides, lawns, waste areas.
Native to North America?
No
Sometimes confused with
- Trifolium aureum:
- central leaflet of leaf without a stalk or on a stalk that is approximately the same length as the stalks of the lateral leaflets and flowers 5-7 mm long (vs. T. dubium, with the central leaflet of leaf on a stalk that is longer than the stalks of the lateral leaflets and flowers mostly 3-4 mm long).
- Trifolium campestre:
- central leaflet of leaf on a stalk 1-3 mm long and flowers mostly 4-5 mm long (vs. T. dubium, with the central leaflet of leaf on a stalk up to 1 mm and flowers mostly 3.5-4 mm long).
![Additional features: Trifolium dubium. ~ By Frank Bramley. ~ Copyright © 2025 New England Wild Flower Society. ~ Image Request, images[at]newenglandwild.org](https://newfs.s3.amazonaws.com/taxon-images-239x239/Fabaceae/trifolium-dubium-af-fbramley.jpg) 
                         
                         
                         
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