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Western Wetland Flora

Field Office Guide to Plant Species

Dwarf Butter-cup
Ranunculus alismifolius Geyer ex Benth.

JPG -- Species Photo JPG -- Distribution Map

Family: Butter-cup (Ranunculaceae)
Flowering: April-June
Field Marks: The bright yellow petals are up to 1/2 inch long, about 3 times as long as the sepals. All the leaves are smooth and lanceolate.
Habitat: Around lakes, along streams, wet meadows, roadside ditches.
Habit: Perennial herb with several thickened roots.
Stems: Upright, often branched, usually rather stout, up to 2 1/2 feet tall, smooth, hollow.
Leaves: Basal leaves and alternate cauline leaves both present, lanceolate, rounded or pointed at the tip, tapering to a long leaf stalk, up to 4 inches long, up to 1 1/2 inches wide, usually without teeth or lobes, smooth.
Flowers: 1-few at the tips of the branches, up to nearly 1 inch across on smooth stalks up to 4 inches long.
Sepals: 5, yellow-green, free from each other, about 1/8 inch long, up to 1/3 as long as the petals.
Petals: 5, bright yellow, free from each other, obovate, 3 times longer than the sepals.
Stamens: Numerous.
Pistils: 30-50 in a rather compact cluster, each with a superior ovary, smooth.
Fruits: Achenes 30-50 in a small spherical head, each achene obovoid, up to 1/8 inch long, with a short, curved or straight beak.
Notes: The leaves are reminiscent of those of Alisma graminea. The common name is not particularly appropriate for this species. The achenes are eaten by small birds and small mammals.

Previous Species -- Subalpine Butter-cup (Ranunculus abortivus)
Return to Species List -- Group 8
Next Species -- Seaside Butter-cup (Ranunculus cymbalaria)

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Page Last Modified: Saturday, 02-Feb-2013 06:28:26 EST
Menlo Park, CA [caww55]