Historical reference: Do not rely on this information. It is very old. About this collection
Buttercup, the popular name for the common yellow-flowered species of Ranunculus (q.v.), especially R. acris, R. repens, and R. bulbosus. R. aeris has a slender cylindrical flower-stalk and spreading sepals; R. repens has long runners, a furrowed flower-stalk, and spreading sepals; and R. bulbosus has a, bulb but no runners, furrowed flower-stalk, and reflexed sepals.