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In this article we will discuss about:- 1. Characters of Combretaceae 2. Distribution of Combretaceae 3. Economic Importance 4. Affinities 5. Important Type.
Characters of Combretaceae:
Flower pentamerous, sepals 4-5, valvate, petals small sometimes absent, stamens 10 in two series; Carpel one, inferior, unilocular; fruit 2-5 angled. Disc is located at the tip of the ovary on the receptacular tube and is represented by hairy outgrowths sometimes. Tannin containing cells occur throughout in the plant body, particularly in the pericarp of the fruit.
A. Vegetative characters:
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Habit:
Mainly trees of shrubs, sometimes sub-scadent.
Root:
Tap, deep and branched.
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Stem:
Erect, hard and woody or sometimes weak and sub-scadent.
Leaf:
Simple, entire, alternate or opposite, exstipulate.
B. Floral characters:
Inflorescence:
Racemose paniculate or spicate.
Flower:
Actinomorphic rarely zygomorphic, hermaphrodite sometimes unisexual by abortion, epigynous; floral axis is carried above the ovary forming a tube.
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Calyx:
Sepals 4-5, rarely more, united to form a calyx tube adnate to ovary and produced beyond it; valvate, persistent.
Corolla:
Petals are usually small, as many as sepals and alternating with them, either valvate or imbricate in aestivation, sometimes absent, polypetalous.
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Androecium:
Stamens 4, 5, 8 or 10, rarely many, usually double the number of sepals, in two whorls (when 8 or 10), filaments are curved inwards in bud, anthers bithecal, versatile; stamens when in two whorls, often obdiplostemonous.
Gynoecium:
Monocarpellary; ovary inferior, 1-celled, generally angled, the angles equal in number and alternating with calyx-segments; ovules 2-5, rarely more, anatropous, pendulous from the top of the ovary on long, often united funicles; style one, long, filiform bearing a pointed, rarely a capitate stigma. The receptacle-tube bears a disc, which is sometimes hairy.
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Fruit:
Leathery, one seeded drupe having angled or winged pericarp.
Seed:
Non-endospermic; spirally twisted cotyledens.
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Pollination:
Entomophilous.
Floral formula:
Distribution of Combretaceae:
Combretaceae or Combretum family or Terminalia family includes 18 genera and 500 species. The largest genera are Combretum of 370 species and Terminalia of 200 species.
Economic Importance of Combretaceae:
1. Food:
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The fruits of Terminalia catappa – Indian almond H. Jungali badam are edible.
2. Medicinal:
Terminalia is the most important medicinal plant. The bark of Terminalia arjuna is used as cardiac tonic; and in feminine diseases T. tomentosa, T. paniculata, T. angustifolia, T. coricea, and T. glabra are some others useful species. Most of them are astringent and administered as purgative, as also in dropsy, diarrhoea, piles, leprosy and cough.
The fruits of T. bellirica H. Bahera and T. Chebula (H. Harach) are of medicinal value.
3. Gum:
The fruits of T. bellirica constitute one of the myrobalans (an adhesive) of commerce.
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The gum exuding from the trunk of Anogeissus latifolia is used in cali coprinting, paper-sizing and confectionery.
4. Timber:
The wood obtained from T. bialata and T. belerica is used for cabinet work furniture and interior fittings.
5. Tannin:
The young fruits of T. alata, T. arjuna, T. chebule, etc. are used for tanning and dyeing.
6. Ornamental:
Quisqualis indica (Rangoon creeper), Terminalia arjuna (Arjun), Bucida, Combretum are of ornamental value.
Affinities of Combretaceae:
Bentham and Hooker and also Hutchinson placed the family in Myrtales. While Engler has included in the sub-order Myrtinae of Myrtiflorae. Takhtajan, Cronquist and Thorne also placed Combretaceae under Myrtales. The Combretaceae shows resemblance with Rhizophoraceae in having inferior ovary. It also resemblances Myrtaceae in its inferior ovary, calyx and corolla.
Common plants of the family:
1. Anogeissus latifolia – a big tree having a cluster of winged fruits.
2. Terminalia arjuna – H. Arjun – smooth bark of mechanical value.
3. Combretum – large woody climber.
4. Quisqualis indica – Rangoon-Creeper – the flowers appearing first at night are white but turning pink at day break.
Important Type of Combretaceae:
Quisqualis indica (Rangoon-Creeper) (Fig. 59.1):
Habit:
A creeping sub-scadent shrub, commonly planted in the gardens.
Root:
Tap-root.
Stem:
Weak, sub-scadent.
Leaf:
Opposite, superposed, simple, ovate, entire, exstipulate, unicostate reticulate.
Inflorescence:
Dense racemose clusters of sweet-scented flowers, which appearing first at night are white but turn pink at day-break.
Flower:
Bracteate, bisexual, regular, epigynous, pentamerous.
Calyx:
Sepals 5, calyx-tube adnate to the ovary and produced beyond it, lobes reflexed. superior.
Corolla:
Petals 5, white at first, turning pink, alternating with the sepals, superior, imbricate in bud.
Androecium:
Stamens ten, free in two whorls, the upper opposite the petals and the lower opposite the sepals, filaments long, anthers dorsifixed, superior.
Gynoecium:
Monocarpellary, ovary 1-celled, inferior, 5-angled, angles alternating with calyx segments; ovules pendulous from the top of the ovary on long united funicles; style one, long filiform; stigma minute, capitate.
Fruit:
Five-angled, one-seeded achene.
Seed:
Small, non-endospermic.
Floral formula:
