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In this article we will discuss about:- 1. Characters of Oleaceae 2. Distribution of Oleaceae 3. Economic Importance 4. Affinities 5. Important Types.
Characters of Oleaceae:
Trees or shrubs, leaves opposite, simple or pinnately compound, stipulate; 2-merous flowers, the 2 anthers with cells back to back; 2-loculed, superior ovary with generally 2 ovules each.
A. Vegetative characters:
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Habit:
Trees or woody shrubs or undershrubs sometimes scandent or twining.
Root:
Tap and branched.
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Stem:
Woody, erect or twining, branched.
Leaf:
Simple or compound pinnately opposite exstipulate, alternate in Jasminium humile; entire, unicostate reticulate venation.
B. Floral characters:
Inflorescence:
Cymose or compound racemes, panicle.
Flower:
Actinomorphic, hermaphrodite rarely unisexual (Fraxinus spp. and some species of Olea), tetramerous, hypogynous.
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Calyx:
Sepals usually 4 or 5 in Fraxinus excelsior and sometimes more than 5 (Jasminum spp.) more or less united, bell-shaped or tubular, usually small, toothed or nearly entire, free in some species, persistent.
Corolla:
Petals 4-5, sometimes more (Jasminum spp.), gamopetalous, salver or funnel shaped or rotate, valvate, imbricate (Jasminum), sometimes as in Fraxinus, 4 petals, rarely free (Fraxinus ornus) or even absent.
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Androecium:
Stamens 2, sometimes 4 (Hesperelaea and Tessarandra), inserted on the corolla-tube or at the base of the petals. Filaments usually short, anthers 2-celled, extrose.
Gynoecium:
Carpels 2, syncarpous; ovary superior, 2-celled, with usually 2 anatropous, ascending or pendulous ovules in each loculus, rarely 4-10 ovules in each loculus; style usually short, simple; stigma terminal simple or bilobed.
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Fruit:
Variable-capsule, samara, berry or drupe.
Seed:
Endospermic and oily.
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Pollination:
Entomophilous.
Floral formula:
Distribution of Oleaceae:
Oleaceae or olive family includes 29 genera and 600 species approximately. Its members are cosmopolitan in distribution but occur in great diversity in temperatate and tropical Asia.
Economic Importance of Oleaceae:
1. Food:
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Fraxinus ornus is cultivated in the Mediterranean countries for the sake of saccharine juice which flows out and coagulates into “Manna” a sugary substance.
2. Medicinal:
Leaves of Jasminum sambac (Arabian Jasmine) are used in India as lactifuge and are said to be as efficacious as belladona. A decoction of the leaves and roots are used for eye-sore. A decoction of roots of Jasminum pubescence has some repute as an antidote for cobra venom while those of J. humile and J. officinale are said to be useful in curing ringworm.
The leaves and flowers of Jasminium grardiflorum contain a resin, salicylic acid, an alkaloid ‘Jasminine’ and an astringent. The whole plant is considered to be anthelmintic, diuretic and emmenagogue.
3. Oil:
Olive oil is obtained from the fruit-pulp and seeds of Olea europea.
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4. Perfumes:
The sweet-scented flowers of Jasminum grandifiorum and J. sambac contain an essential oil which is used in the preparation of well-known perfume, Jasmine.
5. Timber:
The wood of Fraxinus excelsior (Ash), Olea dioica and Olea robusta, yield excellent timber which is hard and durable.
6. Dye:
The corolla of Nyctanthus yields an orange dye.
7. Ornamentals:
Many species of Jasminum, e.g., J. sambac and J. grandifiorum are cultivated as ornamental shrubs on account of their elegant foliage and beautiful sweet-scented flowers. Nyctanthes-arbortristis (Harsinghar) is very popular for its sweet-scented flowers which open at night. Many species of Ligustrum, Syringa (Lilac) and Forsythia are also beautiful ornamentals.
Affinities of Oleaceae:
Hutchinson has placed the family under the order Loganiales related to Loganiaceae. He was, however, of the opinion that the family is an unnatural assemblage considering Fraxinus to be more akin to the Sapindaceae and Ligustrum to Loganiaceae. He establishes its relationship with Rubiaceae and Apocynaceae from which it can be distinguished by the aestivation of corolla, number of stamens, position of ovules and the nature of endosperm.
Common plants of the family:
1. Jasminum – name derived from Jasmine, the Persian name signifying fragrant; cultivated in gardens.
2. Nyctanthus – from Greek nyx, nycols, night and anthos, flower, the flowers open in the evening and fall off the following morning.
Nyctanthus arbor-tristic – Harsingar – ornamental tree.
3. Olea – Latin name of olive, a tree.
4. Osmanthus – a shrub or small ever-green tree.
5. Syringa – a musical pipe, its long, straight branches from which the pith is easily removed to make flute or whistle.
Division of the family and chief genera:
The Oleaceae is divided into two sub-families:
Sub-family I. Oleoideae:
Seeds pendulous. Fruit not vertically constricted.
Tribe I. Fraxineae:
Fruit samara, Genus: Fraxinus.
Tribe II. Syringeae:
Fruit loculicidal capsule. Genus: Syringa.
Sub-family II. Jasminoideae:
Seeds erect. Fruit vertically constricted and divided into two parts by constriction. Genus: Jasminum.
Important Type of Oleaceae:
Jasminum (H. Chambeli) (Fig. 72.2):
Habit:
Shrubby or climbing cultivated in gardens.
Root:
Tap and branched.
Stem:
Branched, erect or climbing.
Leaf:
Opposite rarely alternate, simple, usually compound, imparipinnate, leaflets opposite, nearly sessile, entire, end one the longest.
Inflorescence:
Terminal cymose clusters.
Flower:
Bracteate, hermaphrodite, actinomorphic, pedicellate, complete.
Calyx:
Bell-shaped sometimes cytindrical with 4-10 lobes, teeth short or long, gamosepalous, inferior.
Corolla:
Gamopetalous, tube slender, 4-10 lobed, to be spreading.
Androecium:
Stamens 2, epipetalous, bithecous, anther oblong, filaments short, connective shortly produced.
Gynoecium:
Bicarpellary, syncarpous, bilocular, superior, 2 ovules in each loculus; style slender, stigma capitate or linear.
Fruit:
A berry
Floral formula:
