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Western Wetland Flora

Field Office Guide to Plant Species

White Water Butter-cup
Ranunculus aquatilis L.

JPG -- Species Photo JPG -- Distribution Map

Family: Butter-cup (Ranunculaceae)
Flowering: April-July
Field Marks: This is an aquatic white-flowered butter-cup with much divided submersed leaves. It differs from the similar R. subrigidus by having its flower stalks straight and not curved by fruiting time. This species may have a few 3-lo
Habitat: In ponds and ditches, in streams, vernal pools.
Habit: Perennial herb with submersed stems.
Stems: Submersed, smooth or hairy, up to 3 feet long.
Leaves: Submersed leaves up to 2 inches long, much divided into thread-like segments, smooth or hairy; floating leaves few, simple but often 3-lobed, less than 1 inch wide, smooth or hairy.
Flowers: Several in clusters, up to 1/2 inch across, each flower on a stalk up to 1 1/2 inches long.
Sepals: 5, green, free from each other, up to 1/8 inch long.
Petals: 5, white, free from each other, up to 1/4 inch long.
Stamens: 10-25.
Pistils: Many, each with a superior ovary, smooth.
Fruits: Achenes 15-25 in a cluster at the tip of a straight stalk, each achene up to 1/16 inch long, smooth, with a minute beak.
Notes: The stems will root at the nodes if the plant is stranded on land. The submersed leaves collapse when removed from the water. The achenes are eaten by waterfowl.

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Page Last Modified: Saturday, 02-Feb-2013 06:26:35 EST
Menlo Park, CA [caww55]