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- Dichotomous Key
- Ranunculaceae
- Ranunculus
- Ranunculus aquatilis
Ranunculus aquatilis — white water buttercup, white water crowfoot
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Facts
White water crowfoot has two types of leaves, finely divided underwater leaves and floating or emersed leaves. Sometimes only the submersed leaves are present, sometimes the plant forms mats on the water surface.
Habitat
Lacustrine (in lakes or ponds), riverine (in rivers or streams)
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
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Leaf position
- the leaves are all submerged underwater
- Leaf arrangement
- alternate: there is one leaf per node along the stem
- Leaf blade length
- 20–30 mm
- Petal or sepal number
- there are five petals, sepals, or tepals in the flower
- Petal color
-
- white
- yellow
- Specific leaf type
-
- the leaf has lobes that radiate from a common point, somewhat like a hand
- the leaf is pinnately compound (i.e., it has three or leaflets distributed along a central axis
- Floating leaf shape
- NA
- Fruit type (general)
- the fruit is dry but does not split open when ripe
- Underwater leaf length
- 20–30 mm
-
Clonal plantlets
- Turion length
- 0 mm
-
Flowers
- Anther color
- there is a noticeable pink, reddish or purplish tint to the anthers
- Carpels fused
- the carpel is solitary or (if 2 or more) the carpels are not fused to one another
- Flower lower lip length
- 0 mm
- Flower position
- the flowers are above the surface of the water
- Flower symmetry
- there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
- Inflorescence type
- the flowers grow out of the axil (point where a branch or leaf is attached to the main stem)
- Inflorescence width
- 10–15 mm
- Length of flower stalk
- 10–60 mm
- Length of peduncle
- 10–60 mm
- Nectar spur
- the flower has no nectar spurs
- Number of carpels
- 8–35
- Ovary position
- the sepals and/or petals are attached below the ovary
- Palate on corolla
- no
- Petal and sepal arrangement
- the flower includes two cycles of petal- or sepal-like structures
- Petal appearance
- the petals are thin and delicate, and pigmented (colored other than green or brown)
- Petal color
-
- white
- yellow
- Petal fringed edges
- the petals are not fringed
- Petal fusion
- the perianth parts are separate
- Petal hairs on inner/upper surface
- there are no hairs on the inner/upper petal surface
- Petal length
- 4–7 mm
- Petal number
- 5
- Petal or sepal number
- there are five petals, sepals, or tepals in the flower
- Sepal appearance
- the sepals resemble leaves in color and texture
- Sepal length
- 2–4 mm
- Sepal number
- 5
- Sepals fused only to sepals
- the sepals are separate from one another
- Spur length
- 0 mm
- Stamen number
-
- 10
- 11
- 12
- 13 or more
- Stamen position relative to petals
- NA
- Stamens fused
- the stamens are not fused to one another
- Stamens fused to petals
- the stamens are not fused to the petals or tepals
-
Fruits or seeds
- Fruit beak length
- 0.2–0.5 mm
- Fruit length
- 1–1.8 mm
- Fruit type (general)
- the fruit is dry but does not split open when ripe
- Fruit type (specific)
- the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)
- Fruit width
- 0.8–1.2 mm
-
Glands or sap
- Oil glands on nodes
- none of the nodes have oil glands
- Sap
- the sap is clear and watery
-
Growth form
- Lifespan
- the plant lives more than two years
- Root septa
- the roots do not have transverse septa
- Roots floating in water
- there are no clusters of roots floating in the water
- Turions
- there are no turions on the plant
- Underground organs
- the plant has a rhizome (a horizontal underground stem with roots growing from it)
-
Leaves
- Bract position (Sparganium)
- NA
- Floating leaf basal lobes
- NA
- Floating leaf blade width
- 0 mm
- Floating leaf length
- 0 mm
- Floating leaf shape
- NA
- Floating leaf tip
- NA
- Leaf arrangement
- alternate: there is one leaf per node along the stem
- Leaf blade length
- 20–30 mm
- Leaf blade veins
- the lateral veins radiate from the base and continue to spread away from the centerline of the leaf, or branch off the central vein at intervals
- Leaf position
- the leaves are all submerged underwater
- Leaf special features
- none of the mentioned special features are present
- Leaf-like branch segments
- 0
- Leaf-like branch shape
- the leaf-like branches are round
- Specific leaf type
-
- the leaf has lobes that radiate from a common point, somewhat like a hand
- the leaf is pinnately compound (i.e., it has three or leaflets distributed along a central axis
- Staminate bract edge (Myriophyllum)
- NA
- Stipule fused to leaf
- the stipules are attached to the leaf blade for some part of their length
- Stipules
- the plant has stipules
- Trap-bladder length
- 0 mm
- Underwater leaf air passage number
- At least 1439
- Underwater leaf air passage relative width
- At least 4336
- Underwater leaf air passage row number
- 0
- Underwater leaf blade edges
- the underwater leaf has smooth edges, without teeth
- Underwater leaf blade shape
-
- the underwater leaf blade is capillary (very fine and hair-like)
- the underwater leaf blade is flabellate (fan-shaped)
- the underwater leaf blade is reniform (kidney-shaped; wider than long)
- Underwater leaf length
- 20–30 mm
- Underwater leaf stalk
- yes
- Underwater leaf stalk length
- 2–18 mm
- Underwater leaf tip shape
- the tip of the underwater leaf is rounded, with no point
- Veins in floating leaf
- 0
-
Place
- Habitat
- aquatic
- New England state
-
- Connecticut
- Maine
- Massachusetts
- New Hampshire
- Rhode Island
- Vermont
- Specific habitat
-
- in lakes or ponds
- in rivers or streams
-
Stem, shoot, branch
- Flowering stem growth form
- the flowering stem trails along the substrate, or floats in the water
Wetland status
Occurs only in wetlands. (Wetland indicator code: OBL)
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.
- Connecticut
- unrankable (S-rank: SU), special concern (code: SC)
var. diffusus
- Connecticut
- fairly widespread (S-rank: S4S5)
- Massachusetts
- widespread (S-rank: S5)
- Rhode Island
- extremely rare (S-rank: S1), state endangered (code: SE)
- Vermont
- uncommon (S-rank: S3)
Subspecies and varieties
Our variety is Ranunculus aquatilis L. var. diffusus Withering.
From Flora Novae Angliae dichotomous key
5. Ranunculus aquatilis L. var. diffusus Withering N
white water crowfoot. Batrachium aquatile (L.) Dumort.; B. longirostre (Godr.) F.W. Schultz; B. trichophyllum (Chaix) F.W. Schultz; Ranunculus amphibius James; R. aquatilis L. var. capillaceus (Thuill.) DC.; R. aquatilis L. var. longirostris (Godr.) Lawson; R. aquatilis L. var. subrigidus (W. Drew) Breitung; R. longirostris Godr.; R. subrigidus W. Drew; R. trichophyllus Chaix; R. trichophyllus Chaix var. confervoides (Fries) Rikli; R. trichophyllus Chaix ssp. eradicatus (Laestad.) C.D.K. Cook; R. trichophyllus Chaix var. eradicatus (Laestad.) W. Drew; R. trichophyllus Chaix ssp. lutulentus (Perrier & Song.) Vierh. • CT, MA, ME, NH, RI, VT. Still or slow-moving water of lakes and rivers, commonly in circumneutral to basic water.
Native to North America?
Yes
Sometimes confused with
- Ranunculus flabellaris:
- petals yellow and leaf segments flat (vs. R. aquatilis, with petals white with a yellow base and leaf segments capillary).
Synonyms
- Batrachium aquatile (L.) Dumort.
- Batrachium longirostre (Godr.) F.W. Schultz
- Batrachium trichophyllum (Chaix) F.W. Schultz
- Ranunculus amphibius James
- Ranunculus aquatilis var. capillaceus (Thuill.) DC.
- Ranunculus aquatilis var. diffusus Withering
- Ranunculus aquatilis var. longirostris (Godr.) Lawson
- Ranunculus aquatilis var. subrigidus (W. Drew) Breitung
- Ranunculus longirostris Godr.
- Ranunculus subrigidus W. Drew
- Ranunculus trichophyllus Chaix
- Ranunculus trichophyllus Chaix ssp. eradicatus (Laestad.) C.D.K. Cook
- Ranunculus trichophyllus Chaix ssp. lutulentus (Perrier & Song.) Vierh.
- Ranunculus trichophyllus Chaix var. confervoides (Fries) Rikli
- Ranunculus trichophyllus Chaix var. eradicatus (Laestad.) W. Drew