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 - Hibiscus trionum
 
Hibiscus trionum — Venice rose-mallow
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Facts
Venice rose-mallow has deeply-lobed leaves and large flowers that open for only a short period during the day, giving this species its alternate common name of flower-of-an-hour. It is native to Europe, but due to widespread cultivation in gardens, it has escaped to become a weedy naturalized plant nearly throughout North America. It is found in all New England states in disturbed areas.
Habitat
Anthropogenic (man-made or disturbed 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
 - New Hampshire
 - Rhode Island
 - Vermont
 
 
- Flower petal color
 - 
                                
                                    
- blue to purple
 - yellow
 
 
- Leaf type
 - the leaves are simple (lobed or unlobed but not separated into leaflets)
 
- Leaf arrangement
 - alternate: there is one leaf per node along the stem
 
- Leaf blade edges
 - the edge of the leaf blade has lobes, or it has both teeth and lobes
 
- Flower symmetry
 - there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
 
- Number of sepals, petals or tepals
 - there are five 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
 - 13 or more
 
- Fruit type (general)
 - the fruit is dry and splits open when ripe
 
- Fruit length
 - 10–35 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 spurs
 - the anthers do not have spurs on them
 
- Calyx growth after flowering
 - the calyx grows to cover or partially cover the fruit
 
- Calyx symmetry
 - there are two or more ways to evenly divide the calyx (the calyx is radially symmetrical)
 
- Carpels fused
 - the carpels are fused to one another
 
- Cleistogamous flowers
 - there are no cleistogamous flowers on the plan
 
- Corolla palate
 - no
 
- Corona lobe length
 - 0 mm
 
- Epicalyx
 - the flower has an epicalyx
 
- Epicalyx number of parts
 - 3
 
- Flower description
 - the flower has a superior ovary, and lacks a hypanthium
 
- Flower petal color
 - 
                                
                                    
- blue to purple
 - yellow
 
 
- Flower reproductive parts
 - the flower has both pollen- and seed-producing parts
 
- Flower symmetry
 - there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
 
- Flowers sunken into stem
 - no
 
- Form of style
 - the style is branched above the base
 
- Fused stamen clusters
 - there is one cluster 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
 
 
- Horns in hoods (Asclepias)
 - NA
 
- Hypanthium
 - the flower does not have a hypanthium
 
- Inner tepals (Rumex)
 - NA
 
- Marks on petals
 - the petals have spots or streaks on them
 
- Nectar spur
 - the flower has no nectar spurs
 
- Number of carpels
 - 5
 
- Number of pistils
 - 
                                
                                    
- 1
 - 5
 
 
- Number of sepals, petals or tepals
 - there are five 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 only one cycle of petals or sepals
 
- Petal and sepal colors
 - 
                                
                                    
- blue to purple
 - yellow
 
 
- Petal appearance
 - the petals are thin and delicate, and pigmented (colored other than green or brown)
 
- 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
 - 15–40 mm
 
- Petal number
 - 5
 
- Petal tips (Cuscuta)
 - 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 appendages
 - the sepals do not have appendages on them
 
- Sepal appendages (Oenothera)
 - NA
 
- Sepal number
 - 5
 
- Sepals fused only to sepals
 - the sepals are fused to each other (not other flower parts), at least near their bases
 
- Stamen attachment
 - the stamens are attached at or near the bases of the petals or tepals
 
- Stamen number
 - 13 or more
 
- Stamen position relative to petals
 - NA
 
- 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 splitting
 - the capsule splits by five main valves, teeth or pores
 
- Fruit (pyxis) dehiscence
 - NA
 
- Fruit features (Brassicaceae)
 - NA
 
- Fruit length
 - 10–35 mm
 
- Fruit locules
 - five
 
- Fruit type (general)
 - the fruit is dry and splits open when ripe
 
- Fruit type (specific)
 - the fruit is a capsule (splits along two or more seams, apical teeth or pores when dry, to release two or more seeds)
 
- Legumes (Fabaceae)
 - NA
 
- 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 axile placentation, in which the ovules are attached where the septa of a compound ovary are united, usually on the central axis, or to the septa themselves
 
- Rows of seeds in fruit (Brassicaceae)
 - NA
 
- Schizocarpic fruit compression
 - NA
 
- Schizocarpic fruit segments
 - 0
 
- Seed surface
 - the seed has a surface characteristic other than those listed
 
- 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)
 - anything
 
- Final leaf segment length to width ratio (compound lvs only)
 - 0
 
- 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
 
- 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 edges
 - the edge of the leaf blade has lobes, or it has both teeth and lobes
 
- Leaf blade hairs
 - the leaf blade has branched hairs
 
- Leaf blade length
 - 20–60 mm
 
- Leaf blade shape
 - 
                                
                                    
- the leaf blade is oblong (rectangular but with rounded ends)
 - 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 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 spines
 - there are no spines on the leaf edges
 
- Leaf stalk
 - the leaves have leaf stalks
 
- Leaf teeth and lobes
 - 
                                
                                    
- the leaf blade margin has forward-pointing teeth
 - the leaf has lobes that radiate from the base, somewhat like a hand
 
 
- Leaf type
 - the leaves are simple (lobed or unlobed but not separated into leaflets)
 
- Leaves per node
 - there is one leaf per node along the stem
 
- Pinnately compound leaf type
 - NA
 
- Specific leaf type
 - the leaves are simple (lobed or unlobed but not separated into leaflets)
 
- Stipule features
 - NA
 
- Stipules
 - the plant has stipules
 
 - 
                        
Place
- Habitat
 - terrestrial
 
- New England state
 - 
                                
                                    
- Connecticut
 - Maine
 - Massachusetts
 - New Hampshire
 - Rhode Island
 - Vermont
 
 
- Specific habitat
 - 
                                
                                    
- man-made or disturbed habitats
 - meadows or fields
 
 
 - 
                        
Scent
- Plant odor
 - the plant does not have much of a smell
 
 - 
                        
Stem, shoot, branch
- Branched tendrils
 - NA
 
- Hair between stem nodes
 - the stem has hairs between the nodes
 
- Hairs between stem nodes
 - at least some of the hairs on the stem are branched
 
- Leaves on stem
 - there is at least one full leaf above the base of the flowering stem
 
- Plant height
 - 30–50 cm
 
- Tendril origin
 - NA
 
- Tendrils
 - the plant does not have tendrils
 
 
Wetland status
Not classified
In New England
Distribution
- Connecticut
 - present
 
- Maine
 - present
 
- Massachusetts
 - present
 
- New Hampshire
 - present
 
- Rhode Island
 - present
 
- Vermont
 - present
 
Conservation status
Exact status definitions can vary from state to state. For details, please check with your state.
- Massachusetts
 - unranked (S-rank: SNR)
 
From Flora Novae Angliae dichotomous key
3. Hibiscus trionum L. E
Venice rose-mallow. Trionum trionum (L.) Woot. & Standl. • CT, MA, ME, NH, RI, VT. Fields, roadsides, gardens, railroads, waste areas, wool waste.