Ranunculus sardous
Hairy buttercup
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Family: Ranunculaceae · Type: Herb · Not Native
Ranunculus sardous (Hairy buttercup) is a non-native California herb in the Ranunculaceae family, recognized by papillate fruits with hooked bristles.
Hairy buttercup is a naturalized annual found in northern California Coast, northern Sierra Nevada foothills, and Sacramento Valley in wetlands and ponds at elevations below 300 meters. Flowering from May to July, this plant produces yellow flowers with 5 broad petals 7 to 10 millimeters long. Growing to 18 to 50 centimeters tall with an erect habit, it develops basal roots and multiple stems. Its leaves are distinctively divided into 2 to 6 centimeters wide ovate to heart-shaped segments with crenate-dentate edges, featuring 1 to 2 ternate leaflet arrangements. The fruit develops as a disk-like body with coarsely textured surface, each papilla tipped with a hooked bristle and a small curved beak.
Identification and appearance
Key characters: 32 sympatric species; key feature is papillate fruits with hooked bristles
Habitat and range
Habitat: Ponds, wetlands
Elevation: < 300 m
Outside California: Oregon, eastern United States, Australia, native to Europe
Bloom period
Ranunculus sardous blooms May-Jul.
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 sardous native to California?
No. Ranunculus sardous is not native to California (recorded as not native).
When does Ranunculus sardous bloom?
Ranunculus sardous blooms May-Jul.
What plant family does Ranunculus sardous belong to?
Ranunculus sardous is in the Ranunculaceae family, genus Ranunculus.
What habitat does Ranunculus sardous grow in?
Ranunculus sardous grows in Ponds, wetlands.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · 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.