Yellow Water Butter-cup Ranunculus flabellaris Raf.
Family: Butter-cup (Ranunculaceae)
Flowering: April-August
Field Marks: This species when growing in water has greatly dissected leaves with very narrow segments. The yellow flowers are 3/4-1 1/2 inches across and contain 50-80 stamens.
Habitat: Shallow waters or in mud, in marshes, in wet ditches.
Habit: Aquatic or mud-inhabiting perennial with thread-like roots.
Stems: Floating in water or lying on mud and rooting at the nodes, branched, up to 2 feet long, smooth or hairy.
Leaves: Deeply dissected in aquatic forms, each segment extremely narrow, less divided and with broader segments when rooted in mud, usually smooth.
Flowers: 1-few in a cluster; each flower on a stalk up to 2 inches long.
Sepals: 5, free from each other, greenish yellow, 1/4-1/3 inch long.
Petals: Usually 5, sometimes more, yellow, free from each other, 1/3-3/4 inch long.
Stamens: 50-80.
Pistils: Many in each flower, each with a superior ovary.
Fruits: Many achenes, together in a head, the head nearly 1/2 inch in diameter, each
achene obovoid, up to 1/8 inch long, with a flat beak.
Notes: The achenes are eaten by birds and small mammals.