Ranunculus species: Buttercups

Family

Ranunculaceae

Common Names

Buttercups, crow foot, butter cress, figwort.

Plant Description

Consisting of at least 400 species native to most temperate regions of the world, buttercups can be both weeds or colorful wildflowers that have been hybridized into showy ornamentals. The Asian species (Ranunculus asiaticus) have been selectively hybridized for their double flowering habit. Many species of buttercup are common in meadows and in marshy areas as wild flowers, while some such as the bur buttercup (Ranunculus (Ceratocephalus) testiculatus) are invasive weeds and have caused poisoning in sheep [1]. Over 70 species of native or introduced species of buttercup occur in North America. Ranunculus species are annuals or perennials growing from tuberous roots, rhizomes, or stolons. The leaves are alternate, palmate, simple or compound, margins entire or toothed, basal leaves having long petioles. Flowers can be small or showy, sepals 3 - 5, petals may be absent or as many as 25, color is often yellow, but can be white, red, or green (Fig. 334 and Fig. 335).

Figure 334. Ranunculus acris.

Figure 335. Ranunculus asiaticus hybrid.

Toxic Principle and Mechanism of Action

Ranunculus species contain the irritant glycoside ranunculin that is converted to protoanemonin when the plant tissues are chewed and macerated [2]. Protoanemonin is the vesicant, and it is polymerized to the non-toxic anemonin. The dried plant contains mostly anemonin and is therefore not toxic. Buttercups are most toxic when flowering containing 1 - 2% protoanemonin on a dry weight basis [1].

Risk Assessment

Buttercups are not a significant problem to household pets as the bitter irritant effects of the plants are a deterrent to most dogs and cats. However, the showy "Ranunculus" that are sold as potted plants or as garden ornamentals have the potential to be chewed and eaten by pets.

Clinical Signs

Excessive salivation, vomiting, and diarrhea can be anticipated if buttercups are eaten in quantity.

Treatment if necessary should include activated charcoal (2 - 8 gm/kg body weight orally) and a cathartic such as magnesium sulfate to help in the removal of the plant material from the gastrointestinal tract. Intrvenous fluid therapy is indicated in the dehydrated animal.