Malvaceae Notes
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Morphology of Flowering Plants
Malvaceae
Malvaceae Notes
Malvaceae
Malvaceae, also known as the mallow family, is a group of diverse flowering plants. 244 genera with almost 4225 species are known in this family. The most commonly known members of the family include hibiscus, okra, cotton, and cacao.
Classification of Malvaceae
- Domaine: Eukarya
- Kingdom: Plantae
- Division: Angiospermae
- Class: Dicotyledonae
- Order: Malvales
- Family: Malvaceae
Characteristics of Malvaceae
Leaves and Stem
- The members of the family exist as shrubs or herbaceous plants, while some are also seen in the form of trees or lianas.
- The leaves are borne alternately and are often palmately lobed, or they can also be compound and palmately veined.
- The leaf margin is entire in majority, but some species also have dentate leaf margins.
- Stipules are found at the base of the leafstalk.
- The stems contain mucus canals and mucus cavities.
- Hairs are common on the stem in a stellate, radiating star-like manner.
Flowers and Fruits
- The flowers are borne in either definite or indefinite axillary inflorescence.
- The flowers also bear bracts.
- The flowers can be both unisexual or bisexual.
- The symmetry of the flower is actinomorphic.
- The presence of epicalyx is the characteristic feature of the family.
- They also have nectaries with glandular hairs inside them found on the sepals.
- The fruits are borne in the form of nuts, capsules, or schizocarps.
Pollination
- The members majorly undergo cross-pollination. Self-pollination is avoided by means of protandry (the pollens are shed before the maturity of ovules).
- Pollination is mostly done by insects, i.e., they are entomophilous.
Floral Arrangement of Malvaceae
The floral arrangement of Malvaceae flowers is as follows:
- They have five valvate sepals (gamosepalous).
- Five imbricate petals (polypetalous).
- Stamens can be 5 to numerous in number.
- The pistil is composed of two to numerous carpels.
- The ovary is at the superior position.
- The placentation is axile.
Importance
The Malvaceae family consists of species that are economically very important. Some of the important species with the products they produce are listed below:
- Gossypium sp. (cotton)
- Corchorus sp. (tossa and white jute)
- Hibiscus sp. (hibiscus)
- Theobroma cacao (cacao)
- Abelmoschus esculentus (okra)
- Cola sp. (kola nut)
- Abelmoschus moschatus (fragrance products)
- Malva sp. (ornamentals)
Habit
Herbs, shrubs (e.g., Hibiscus rosa-sinensis) or rarely trees.
Root
Tap root system.
Stem
Stem is erect, herbaceous or woody, and branched.
Leaves
- Leaves are alternate and stipulate.
- They are simple.
- Reticulate Venation
Inflorescence
Usually the flowers are solitary axillary or terminal.
Flowers
- Actinomorphic, bisexual, pentamerous.
Calyx
- Sepals 5, gamosepalous valvate aestivation.
Corolla
- Petals 5, polypetalous. They show twisted or imbricate.
Androecium
- Indefinite stamens.
- They are monadelphous.
- Filaments of the stamens are united to form a long staminal tube.
- Stamens are epipetalous.
- Anthers are monothecous.
Gynoecium
- Multi carpellary [pentacarpellary in Hibiscus (syncarpous)].
- Ovary is superior, multilocular.
- The placentation is axile.
Fruit
Fruit is capsule or berry.
Seed
Endospermic
Floral formula
Br K(5)C5A∞G (5-∞)
Examples
- Bhindi or Okra or Lady's finger (Abelmoschus esculentus).
- Cotton or Kapas (Gossypium sp.): Source of oil and fibre.
- Cotton fibre is obtained from seed coat of Gossypium.
- Madras Hemp (Hisbiscus cannabinus): Also called patson & used in rope industry.
- Gurhal or China rose (Hibiscus rosa sinensis): Ornamental.
Note: Most of the economically important fibre yielding plants belong to family Malvaceae.
