Ranunculus flabellaris
Yellow water buttercup
(c) Eric Knight, some rights reserved (CC BY) · licence
Family: Ranunculaceae · Type: Herb · Native
Ranunculus flabellaris (Yellow water buttercup) is a native California herb in the Ranunculaceae family, recognized by aquatic habit with large yellow petals distinctive.
Yellow water buttercup is a California native perennial found in the Klamath Ranges, northern coastal redwood habitat, and North Coast Mountains in shallow water and drying mud areas at elevations of 900 to 2,000 meters. Flowering from April to August, this plant produces yellow flowers 7 to 12 millimeters wide with distinctive rounded petals. Growing up to 70 centimeters tall, it forms floating or decumbent stems that root at lower nodes and spread across wet surfaces. Its distinctive leaves are semicircular to kidney-shaped, with blades that are deeply lobed or dissected into rounded or thread-like segments. The fruit is small and lenticular, with a straight lanceolate beak 1 to 1.8 millimeters long.
Identification and appearance
Key characters: 40 sympatric species; aquatic habit with large yellow petals distinctive
Habitat and range
Habitat: Shallow water, drying mud
Elevation: 900-2000 m
Outside California: to British Columbia, New Brunswick, North Carolina
Bloom period
Ranunculus flabellaris blooms Apr-Aug.
How to tell it apart
vs Lasthenia: Ranunculus has separate petals around a central disk; Lasthenia has many tiny ray flowers around a disk (composite head).; vs Bowlesia: Ranunculus has glossy yellow petals in conspicuous flowers; Bowlesia has tiny white flowers in umbels with divided leaves.; vs Potentilla: Ranunculus has nectaries at petal bases and many pistils; Potentilla has no nectaries and styles attached to ovary sides.; vs Papaver: Ranunculus has 5 petals and many pistils; Papaver has 4 crinkled petals and a single large stigma disk.; vs Oxalis: Ranunculus has glossy separate petals; Oxalis has clover-like leaves and tubular flowers that close at night.
Frequently asked questions
Is Ranunculus flabellaris native to California?
Yes. Ranunculus flabellaris is native to California (recorded as native).
When does Ranunculus flabellaris bloom?
Ranunculus flabellaris blooms Apr-Aug.
What plant family does Ranunculus flabellaris belong to?
Ranunculus flabellaris is in the Ranunculaceae family, genus Ranunculus.
What habitat does Ranunculus flabellaris grow in?
Ranunculus flabellaris grows in Shallow water, drying mud.
Related species
Other California species in the same genus, family, or bioregion.
- Ranunculus flammula — Creeping buttercup
- Ranunculus flammula var. flammula — Greater creeping spearwort
- Ranunculus flammula var. ovalis — Greater creeping spearwort
- Ranunculus glaberrimus — Sagebrush buttercup
- Ranunculus glaberrimus var. ellipticus — Elliptical buttercup
- Ranunculus glaberrimus var. glaberrimus — Sagebrush buttercup
Sources: Jepson eFlora · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.