Ranunculus aquatilis L.

white water buttercup, white water crowfoot

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New England Distribution

Adapted from BONAP data

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North America Distribution

Adapted from BONAP data

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Facts About

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)

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
Show All Characteristics
  • 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)

New England Distribution and Conservation Status

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)

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

Family

Ranunculaceae

Genus

Ranunculus

Notes on Subspecies and Varieties in New England

Our variety is Ranunculus aquatilis L. var. diffusus Withering.

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Information from Dichotomous Key of Flora Novae Angliae

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.