In this article we will discuss about:- 1. Characters of Violaceae 2. Distribution of Violaceae 3. Economic Importance 4. Affinities 5. Important Type.
Characters of Violaceae:
Plants mostly herbs rarely shrubs, all leaves basal, simple, stipulate; flowers zygomorphic rarely actinomorphic, hermaphrodite, hypogynous; sepals, petals and stamens 3 each; gynoecium tricarpellary, syncarpous, unilocular with parietal placentation; fruits capsule.
A. Vegetative characters:
Mostly herbs – annual or perennial, some shrubs or under-shrubs rarely climbers (Anchietea).
Herbaceous or woody, erect, usually un-branched.
Simple, entire or variously toothed, with a marked tendency to be cordate in form, all basal in some species, but in others alternate or rarely opposite (Hybanthus), stipulate, stipules permanent and foliaceous (Viola spp.).
B. Floral characters:
Solitary or terminal spike.
Bracteate, bracteolate (two bracteoles), perfect, regular (Rinorea syn. Alsodeia) or irregular (Viola, with a large spurred anterior petal), pentamerous, hermaphrodite or rarely polygamous, hypogynous, sometimes cleistogamous.
5 sepals, free or somewhat connate to form a ring around the ovary. Sepals appendiculate, prolonged below into a short obtuse blade.
5 petals, free, equal or unequal, the lowest (anterior) one often large and saccate or spurred, variously coloured.
Stamens 5, joined in a ring around ovary and style; anthers introrse, connectives of anterior stamens spurred, the spurs enter the spur, formed by the anterior petal.
Carpels 3, rarely 2-5 (Melicystus, Leonia), syncarpous unilocular with parietal placentation, ovules one to numerous on each placenta; style simple or divided; stigmas of various shapes, often hooded.
A loculicidal capsule.
Endospermic, smooth, winged, testa shining.
Entomophilous; cleistogamous flowers (Viola tricolor) are self pollinated.
Distribution of Violaceae:
Violaceae or violet family comprises of 22 genera and approximately 900 species, which are widely distributed in all continents. In India it is represented by 3 genera – Viola, Vahila and Hybanthus.
Economic Importance of Violaceae:
The dried flowers of Viola odorata (Vern. Banafsha) are used against cough, influenza and respiratory diseases, Roots of Hybanthus enneaspermus are used in urinary infections and gonorrhoea.
Oil extracted from flowers of Viola odorata is used in perfumes, while its leaves yield an essential oil, used in scenting soaps.
Violas, violets (Viola odorata) and pensies (V. tricolor) are commonly cultivated in gardens for their beautiful and colourful flowers.
Affinities of Violaceae:
The phylogenetic position of family is uncertain. Wettstein, Bentham and Hooker placed it in the order Parietales. Rendle included in Guttales. Hellier opioned that the Violaceae is akin to Balsaminaceae; Flacourtiaceae and Turneraceae due to the spurred corolla and thus included it as a primitive member of his Polygalines. Hutchinson placed it in the Violales.
Common plants of the family:
1. Viola odorta L.:
Sweet violet or wild pansy – an ornamental plants.
2. Viola canina:
Dog violet. Cultivated; leaves used in pulmonary troubles.
3. Hybanthus (Syn. lonidium) enneaspermus:
Roots used for intestinal disorders of children.
Division of family and chief genera:
Violaceae is divided into to sub-families:
Sub-family I. Leoniodeae:
Stamens connate forming a column. Fruit nut-like with hard pericarp. Example – Leonia.
Sub-family II. Violoideae:
Stamens free or more of less connate; fruit – a capsule. Example- Viola.
Important Type of Violaceae:
Viola tricolor (Pansy; Fig 33.1):
Annual garden plant.
Erect, branched, angular, green, fistular, herbaceous.
Cauline and ramal, simple, alternate, stipulate, stipules leafy, unicostate reticulate; crenate, acute, glaucous.
Bracteate, two bracteoles, pedicellate, complete, hypogynous, hermaphrodite, zygomorphic, colour variable.
5 sepals, free, quincuncial, green, inferior, sepals appendiculate.
5 petals, polypetalous, imbricate, anterior petal produced into a spur, in which the honey produced by the spurs of the connectives of two anterior stamens is collected.
Stamens 5, connate, forming a ring around the ovary, filaments small, anthers adnate, connectives of anterior pair of stamens are spurred, which project into the spur of the anterior petal.
Carpels 3, syncarpous; ovary superior, unilocular with numerous ovules attached to parietal placentae; style short, filiform; stigma swollen.
A loculicidal capsule.
Numerous, ovoid, tough and smooth.