In this article we will discuss about:- 1. General Characters of Sterculiaceae 2. Floral Formula of Sterculiaceae 3. Number and Distribution 4. Common Plant 5. Affinity and Economic Importance.
General Characters of Sterculiaceae:
Plants—generally trees or shrubs, sometimes herbs, with stellate hairs and mucilage. Leaves—alternate, simple, entire or palmately lobed or compound, stipulate. Inflorescence—usually cymose, axillary or terminal. Flowers—regular or less often zygomorphic, bisexual (sometimes unisexual, e.g., Heritiera, Sterculia), hypogynous.
Sepals—3-5, more or less slightly united at the base, valvate. Petals—5, often reduced in size (sometimes absent, e.g., Heritiera, Sterculia),free sometimes adnate to the base of the staminal column, twisted. Stamens—numerous in two whorls (those of outer whorl staminodial or 0, and those of inner whorl usually fertile) or monadelphous, anthers. 2-celled.
Carpels—usually 5, syncarpous, sometimes almost free excepting the styles and stigmas (e.g., Sterculia); ovary superior, often stalked, 4—5-celled with two to numerous anatropous ovules in each cell; styles as many as carpels, free or united. Fruit—capsule or follicle, dehiscing along the ventral suture. Seeds—with fleshy endosperm and an embryo with flat, folded or rolled, leafy cotyledons.
Floral Formula of Sterculiaceae:
Number and Distribution of Sterculiaceae:
This family consists of 50 genera and about 750 species which are found in tropical and subtropical regions.
Common Plants of Sterculiaceae:
(1) Sterculia foetida L. and S. colorota = Firmiana colorata R. Br. are large trees planted on roadsides.
(2) S. alata Roxb., an avenue tree.
(3) Abroma augusta L., chiefly planted for medicinal purposes.
(4) Pterospermum acerifolium Willd., an avenue tree which produces fragrant flowers with fleshy sepals; P. semisagittatum Ham., another common tree.
(5) Heritiera minor Roxb., abundantly found in the Sundribans which yields the best fire-wood.
(6) Helicteres isora L., a shrub with spirally twisted follicles.
(7) Kleinhovia hospita L., commonly planted on roadsides.
(8) Melochia corchorifolia L., a common weed of waste places, dry-fields and grassy glades.
(9) Bastard cedar (Guazuma tomentosa Kunth.).
(10) Noon-flower (Pentapetes phoenicea L.), a common garden herb with pink-red flowers.
(11) Cocoa tree (Theobroma cacao L.), chiefly cultivated in Southern India and Ceylon for preparing cocoa and chocolate from the roasted seeds.
(12) Waltheria indica L., a common weed of waste places.
(13) Buettneria herbacea Roxb., a herb.
(14) Dombeya mastersii, a common garden plant.
Affinity and Economic Importance of Sterculiaceae:
This family is allied to Tiliaceae, Malvaceae and Bombacaceae, but readily distinguished by the absence of epicalyx, definite number of stamens and stalked ovary. It differs from Malvaceae in having 2-celled anthers, and from Bombacaceae in presence of copious endosperm, androecium of typically 5 fertile stamens alternated with equal number of staminodes, and absence of a pithy or woolly pericarp.
Economic Importance of Sterculiaceae:
This family is economically important. The most important plant is Theobroma cacao from the seeds of which cocoa and chocolate are prepared. The root of Abroma is used in medicine. Heritiera supplies fire-wood. Cola vera Schum. yields a kind of nut. Some plants are ornamentals, such as, Sterculia, Dombeya, Cola, Pterospermum, Kleinhovia, Guazuma, etc.
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