PHENOLOGY: The abortive buttercup flowers April and May, the cursed buttercup May through August, and the northern buttercup April through June.
DISTRIBUTION: The buttercups are common in Pennsylvania. The abortive buttercup inhabits moist or dry woods; the cursed buttercup, marshes, ditchbanks, and swampy meadows; and the northern buttercup, wet woods and meadows.
PLANT CHARACTERISTICS: Ranuncujus abortivus has petals: yellow, 2-3 mm long, equal to or smaller than the sepals: achenes: with a very short beak, in a short, ovoid head on a villous receptacle. R. scleratus has petals: yellow, 2-3 mm, shorter than the sepals; achenes: nearly beakless, numerous in a short, cylindric head. R.. septentrionalis has petals: yellow, 7-l5 mm, about 2x longer than the sepals; achenes: with a straight beak, 1.8-3 mm long.
POISONOUS PARTS: Fresh leaves and the inflorescence are toxic. Dried material in hay reportedly is not poisonous. Toxicosis varies with amount ingested, stage of plant growth (most toxic at time of flowering), speed and degree of digestion or release of the toxin, growing conditions of the buttercup, and general health or susceptibility of the animal.
SYMPTOMS: Severe gastrointestinal irritation indicated by salivation, decreased appetite, colic, diarrhea. and slow pulse result from poisoning. Milk from affected cows may be bitter and/or reddish. Convulsions, sinking of eyes in their sockets, hematuria, and blindness are seen in severe cases. Horses, goats, and pigs show irritated tissues of the oral cavity. Convulsions may end in death. Buttercup toxicosis displays pulmonary congestion and ecchymotic hemorrhages on the pleural surfaces on postmortem examination.
POISONOUS PRINCIPLES: Toxicity is due to the unstable irritant oil protoanemonin. This oil is volatile and yellow due to lactone. R.. scleratus contains the highest concentration of the oil.
SPECIES OF ANIMAL AFFECTED: All classes of livestock are susceptible.
CONFUSED TAXA: Numerous unrelated plants have 5 bright, yellow petals, although only Ranunculus petals are shiny and porcelainlike. Some members of the Rosaceae have flowers that might superficially resemble those of buttercups. However, the leaves of the rose family bear stipules, which are absent in Ranunculus.
TREATMENT: (11)(b); (26); (5- at a rate of 2 mg subcutaneously. repeated as necessary); (27); (6)
OF INTEREST: Literature records a case of two heifers that were successfully treated for cursed buttercup poisoning. Upon returning to pasture, they selectively ate the R.. scleratus despite ample presence of better forage. These cows apparently developed a desire for this plant after having eaten it as a part of their diet. However, buttercups usually are strongly distasteful to grazing animals and are eaten as a last resort after depletion of more desirable forage.