In this article we will discuss about:- 1. General Features of the Violaceae 2. Floral Range in the Violaceae 3. Divisions 4. Position and Affinity 5. Number and Distribution 6. Commonly Occurring Plants 7. Economic Aspects.
General Features of the Violaceae:
Habit – Herbs or shrubs, rarely climbing.
Leaves – Alternate, simple, stipulate.
Inflorescence – Solitary or terminal spikes with bracts and bracteoles.
Flowers – Bisexual, regular or irregular.
Calyx – Sepals 5, imbricate, persistent.
Corolla – Petals 5, anterior one spurred; imbricate or twisted.
Androecium – Stamens 5; filaments short; connective of anther dilated or prolonged, connivent over pistil.
Gynoecium – Carpels 3; ovary superior unilocular; ovules 1 or more, campylotropous; placentation parietal; stigma curved or s-shaped.
Fruit – Capsule.
Seeds – Subglobose or ovoid, albuminous; embryo straight.
Floral Range in the Violaceae:
The flowers of the Violaceae are almost regular, as in Allexis, Gloeospermum and Rinorea. They may be slightly irregular, e.g., Amphirrhox or highly irregular, e.g., Hyhanthus and Viola.
The members of each calyx are generally free, but somewhat united in Leonia and Melicytus. The sepals are also uniform in size and green in colour. They may be appendiculate, as in Viola. The petals are also large and coloured.
The stamens and carpels vary in number and arrangement. The stamens may be monadelphous as in Agatea or diadelphous as in Anchietea. The carpels are 4 or 5 (Leonia) and 2 or 5 (Melicytus). In Viola, the connective of the anterior pair of anthers is spurred or it may be appendaged.
Divisions of the Violaceae:
The Violaceae is divided into two subfamilies:
Subfamily I. Leonioideae:
Stamens united into a column. Fruit nut-like with a woody pericarp. Example: Leonia.
Subfamily II. Violoideae:
Stamens somewhat united. Fruit a capsule. Example: Viola.
Position and Affinity of the Violaceae:
The phylogenetic position of the Violaceae is uncertain. The family indicates a relationship with the Bixaceae and hence brought close to it by Bentham-Hooker. Hallier opined that the Violaceae is akin to the Balsaminaceae, Flacourtiaceae and Turneraceae due to the spurred corolla and thus included it as a primitive member of his Polygalines. Bessey retained it in the Guttales. In the arrangement of Rendle as well as Wettstein, the family appeared under the Parietales. Hutchinson placed it in the Violales.
Number and Distribution of the Violaceae:
Twenty two genera and approximately 900 species make up the Violaceae. Although widely distributed in all continents, the plants of the family are mainly natives of warmer climate.
Commonly Occurring Plants of the Violaceae:
Hybanthus enneaspermits (L.) F.V. Muell is a small branching annual herb.
Sweet Violet (Viola odorata L.) and Heart’s ease or Wild Pansy (V. tricolor L.) are ornamental plants.
Economic Aspects of the Violaceae:
The plants of the Violaceae are chiefly important as garden plants. Anchietea salutaris, Cornostylis hybanthus, Hybanthus ipecacuanha, Viola canescens and V. cinerea are of medicinal value. Leonia glycycarpa yields edible fruits. A perfume is extracted from the flowers of V. odorata, while the leaves of the same plant produce an essential oil which is used for scenting soaps.
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