Northern Prairie Wildlife Research Center
Swamp Buttercup (Ranunculus septentrionalis)
- Family: Buttercup (Ranunculaceae)
- Flowering: April-June.
- Field Marks: This buttercup has waxy yellow petals longer than the sepals, stalked leaflet segments, stems that lie or creep along the ground, and flattened achenes.
- Habitat: Along streams, in damp woods.
- Habit: Trailing or ascending perennial herb with fibrous roots.
- Stems: Usually trailing or creeping, sometimes ascending, hollow, smooth or sometimes hairy, up to 2 1/2 feet long.
- Leaves: Alternate, pinnately divided into usually 3 leaflets; each of these leaflets stalked, usually toothed and sometimes divided again, smooth or less commonly hairy.
- Flowers: 1-several, slender stalked, yellow, up to 1 1/2 inches across.
- Sepals: 5, green, free from each other, smooth or hairy, up to 1/2 inch long, pointing downward.
- Petals: 5, yellow, waxy, free from each other, up to 2/3 inch long, longer than the sepals.
- Stamens: Numerous.
- Pistils: Numerous, free from each other, smooth.
- Fruits: Nearly round heads of short-beaked achenes; each achene flattened, up to 1/6 inch long, with a curved beak to one side.
- Notes: This is an extremely variable species, easily confused and often intergrading with other large-flowered buttercups.
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