Herbs, shrubs, or small trees. Leaves usually alternate, simple, entire lobed or cut, stipulate. Flowers regular or irregular, axillary, solitary or arranged in cymes or panicles, rarely racemose. Sepals 5, equal or unequal, imbricate. Petals 5, hypogynous, equal or unequal, lower one sometimes spurred, usually imbricate. Stamens 5, hypogynous; filaments short, broad; anthers erect, free or connate round the pistil; connective broad, usually produced beyond the cells into an appendage. Ovary free, 1-celled, with page 443–5 parietal placentas; ovules many or few to each placenta. Fruit either a 3–5-valved capsule or a berry. Seeds usually small; embryo straight, in the axis of fleshy albumen.

An order scattered over the whole world, containing 22 genera and about 250 species. The roots of many of the species are emetic, and are used as a substitute for ipecacuanha. One of the New Zealand genera is found in most countries; the other two have a very limited distribution outside the colony.

Herbs. Flowers irregular, the lower petal produced into a spur. Fruit a capsule	1. Viola.
Trees or shrubs. Flowers regular. Fruit a berry. Anthers free	2. Melicytus.
Anthers coherent	3. Hymenanthera.