Violaceae

Violaceae is a family of flowering plants in the order Malpighiales, within the rosid clade. The family comprises about 18 genera and roughly 800 species, with Viola being the largest and best known genus. Viola includes violets, pansies, and heartsease; other genera such as Hybanthus contribute additional diversity, particularly in tropical and Southern Hemisphere floras.

Most Violaceae are herbaceous plants, though a few tropical genera include shrubs. Leaves are typically alternate and simple, often with a cordate base. Flowers are usually zygomorphic and bisexual, with five petals. In many genera, the lowest petal forms a nectar spur that attracts pollinators; the two lateral petals often appear as wings, and the three petals together create a bilateral floral shape. The sepals are usually small, greenish, or lightly colored. The ovary is generally superior, and the fruit is a capsule that dehisces to release seeds. In some species, seeds bear elaiosomes that facilitate myrmecochory (dispersal by ants).

Distribution is cosmopolitan, with the greatest diversity in temperate regions of the Northern Hemisphere. Hybanthus and other tropical genera extend into Africa, Asia, and Australasia. Habitats range from woodland understories and meadows to disturbed sites and, in cultivation, ornamental gardens.

Phylogenetically, Violaceae is recognized as a distinct family within Malpighiales, and molecular data have helped clarify relationships among its genera, particularly the placement and evolution of Viola relative to other lineages in the family.

Uses include ornamental cultivation for Viola species, valued for their attractive and fragrant flowers. Some species have traditional medicinal uses and historical significance in perfumery, notably Viola odorata.