Ranunculaceae, the Buttercup family, is a large family, globally, it consists of around 1,800 species in about 50 genera. The family occurs throughout the world, but is most abundant in temperate and cool regions of the northern and southern hemispheres. Ranunculus is Latin for "a little frog", the name applied by Pliny the Elder (23-79 A.D.) to a group of plants in this family that grows where frogs abound.
It's not an economically important family. The commercially available species are almost all ornamentals. Some genera are important as poisonous plants. The poisonous properties of Aconitum and Delphinium are well known, particularly to those in involved with cattle. Many, possibly most, other genera contain poisonous species. The compounds involved vary but include alkaloids (in Aconitum and Delphinium), protoanemonin (in Anemone, Clematis, and Ranunculus), and cardiac glycosides (in Helleborus). A drink of Aconitum tea was the lethal drug used for giving the death penalty in ancient times.
Almost all members of the Ranunculaceae are herbaceous, but most species of Clematis are woody vines. The leaves are usually basal or alternate, but are opposite in Clematis. The leaves are usually without stipules, but stipules are present in Thalictrum, Caltha, and
Ranunculus.
The flowers are usually radially symmetric and bisexual, but Delphinium and Aconitum are bilaterally symmetric and Thalictrum has unisexual flowers. When both sepals and petals are present, there are usually 5, but sometimes 4, and sometimes no petals, but brightly colored sepals. The petals may have spurs that run between the sepals (as with columbines), or only some petals with spurs that run into the sepals (as in delphiniums).
The flowers have numerous stamens, and either many pistils that develop into single-seed fruit or a few separate pistils that develop into many-seeded fruits. Fruits are either pods (follicles), seed-like (achenes), or berries.