Viola
Annual, biennial or perennial herbs, glabrous or pubescent. Leaves alternate, in basal rosette or along stem, petiolate; lamina more or less circular to lanceolate, serrate, crenate or almost entire, the teeth glandular; stipules free or united with petiole, persistent. Flowers nodding, solitary on slender axillary scapes with a pair of bracteoles near or above the middle. Sepals entire or minutely toothed-fimbriate, with basal appendages; lower (anterior) petal usually spurred or pouched, lateral petals often bearded within; staminal filaments short or absent, the 2 lowermost anthers with basal spur; ovary glabrous or pubescent, style usually bent, stigma clubbed, lobed or truncate. Fruit a globose to more or less cylindric capsule, glabrous or pubescent, elastically dehiscing into 3 boat-shaped valves; seeds 2–many, smooth or minutely rugose.
About 450 species, mostly in temperate regions; c. 18 species in Australia of which 5 are introduced.
Entwisle, T.J. (1996). Viola. In: Walsh, N.G.; Entwisle, T.J., Flora of Victoria Vol. 3, Dicotyledons Winteraceae to Myrtaceae, pp. 82–84. Inkata Press, Melbourne.