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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:
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Habit:
Mostly herbs – annual or perennial, some shrubs or under-shrubs rarely climbers (Anchietea).
Root:
Tap, root.
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Stem:
Herbaceous or woody, erect, usually un-branched.
Leaf:
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:
Inflorescence:
Solitary or terminal spike.
Flower:
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.
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Calyx:
5 sepals, free or somewhat connate to form a ring around the ovary. Sepals appendiculate, prolonged below into a short obtuse blade.
Corolla:
5 petals, free, equal or unequal, the lowest (anterior) one often large and saccate or spurred, variously coloured.
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Androecium:
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.
Gynoecium:
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.
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Fruit:
A loculicidal capsule.
Seed:
Endospermic, smooth, winged, testa shining.
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Pollination:
Entomophilous; cleistogamous flowers (Viola tricolor) are self pollinated.
Floral formula:
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:
1. Medicinal:
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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.
2. Oil:
Oil extracted from flowers of Viola odorata is used in perfumes, while its leaves yield an essential oil, used in scenting soaps.
3. Ornamentals:
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.
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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):
Habit:
Annual garden plant.
Root:
Tap-root.
Stem:
Erect, branched, angular, green, fistular, herbaceous.
Leaf:
Cauline and ramal, simple, alternate, stipulate, stipules leafy, unicostate reticulate; crenate, acute, glaucous.
Inflorescence:
Solitary axillary.
Flower:
Bracteate, two bracteoles, pedicellate, complete, hypogynous, hermaphrodite, zygomorphic, colour variable.
Calyx:
5 sepals, free, quincuncial, green, inferior, sepals appendiculate.
Corolla:
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.
Androecium:
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.
Gynoecium:
Carpels 3, syncarpous; ovary superior, unilocular with numerous ovules attached to parietal placentae; style short, filiform; stigma swollen.
Fruit:
A loculicidal capsule.
Seeds:
Numerous, ovoid, tough and smooth.
Floral formula:
