Tall buttercup (
Ranunculus acris) is a perennial forb that is native to central and northeastern Europe. It's found throughout the United States, particularly in damp meadows, grasslands and overgrazed horse pastures.
R. acris flowers in late spring, with peak growth during the early summer months.
Toxic components
All parts of
R. acris contains ranunculin, a type of glycoside that is able to convert into protoanemonin, which is toxic to horses. Protoanemonin can bind to certain proteins and causes
contact dermatitis and ulceration of the mouth and damage to the digestive system. The toxin is released when the plant is chewed or otherwise wounded. It is at its highest concentration during the flowering stage.
R. acris is usually avoided by horses, however a starving horse in an overgrazed pasture might be more willing to try grazing this flower.
