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In this article we will discuss about:- 1. Characters of Magnoliaceae 2. Distribution of Magnoliaceae 3. Economic Importance 4. Affinities.
Characters of Magnoliaceae:
Trees and shrubs; two ranked stipulate leaves, stipules enclose young buds; flowers hermaphrodite, actinomorphic, large; perianth usually trimerous, whorled or spiral; stamens and carpels numerous; apocarpous, spirally arranged on elongated axis, fruit an etario of follicles or berries, sometimes samara.
A. Vegetative Characters:
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Habit:
Trees or shrubs sometimes climbing. Oil sacks present in stem and leaves.
Root:
Tap branched.
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Stem:
Erect, aerial, woody, branched.
Leaves:
Alternate, simple, entire, commonly ever-green, coriaceous, stipules large (Magnolia) covering young leaves.
B. Floral Characters:
Inflorescence:
Solitary terminal or axillary.
Flower:
Largest and sometimes, 25 cm in diameter (Magnolia, Fraseri), complete, regular, actinomorphic, unisexual (Drimys), usually bisexual, hypogynous, aromatic. Floral axis (torus) long to long convex.
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Perianth:
Nine to many, free, all alike and petaloid or the three outer ones green (Liriodendron), arranged in whorls of three, imbricate and cyclic (Magnolia and Michelia) or acyclic (spiral) arranged on an elongated or semi-elongated convex torus, free, inferior.
Androecium:
Stamens many, free, often spirally arranged in a beautiful series, filaments short or absent, anther lobes linear, with a prolonged connective.
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Gynoecium:
Carpels numerous, free, superior, arranged spirally on a cone-shaped elongated thalamus (gynophore), rarely carpels are fused, e.g., Zygogynum, placentation marginal.
Fruit:
An aggregate of berries or follicles, sometimes, a samara as in Liriodendron.
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Seed:
Large, with abundant oily endosperm, and bright or orange testa which makes them highly decorative.
Pollination:
Entomophilous due to large and scented flowers.
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Floral formula:
Distribution of Magnoliaceae:
Magnoliaceae or the Magnolia family embraces 10 genera and about 100 species. The members of this family belong to the temperate regions of northern hemisphere, with centres of distribution in eastern Asia, Malaysia, eastern North America, West Indies, Brazil and North-east and south east India.
Economic Importance of Magnoliaceae:
1. Medicinal:
The root bark and dried roots of Michelia champaca are used as purgative, while the flowers and fruits are used as carminative and in certain renal troubles and venerial diseases like gonorrhoea. The bark of Drimys winteri and Illicium uerum is useful in medicine.
2. Timber:
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The wood of Michelia excelsa is an excellent commercial timber known as “white wood”. M. acuminata, Manglietia hookeri, Michelia baillonii, M. dottsopa and Pachylarnax pleiocarpa produce valuable timber used for mill work, furniture, musical instruments, toys etc.
3. Ornamentals:
The species of Magnolia and Michelia are of surprising beauty because of their conspicuous white and yellow-tinted, fragrant flowers. Flowers of Michelia champaca are used by womens to ornament their hair and also offered in temples.
Michelia champaca yields ‘champaca oil’ from the flowers, camphor from the wood and scented water from the leaves.
Affinities of Magnoliaceae:
Magnoliaceae is akin to Annonaceae, Engler, Rendle and other botanists put the Magnoliaceae under the Ranales. But Hutchinson placed the family within the Magnoliales and considered it as the most primitive among the dicotyledons.
The primitiveness of this family is shown by the spiral arrangement of stamens and carpels and apocarpous pistil – characters also shared with the Ranunculaceae. Smith, however, cast some doubt on the assumption of the primitive nature of the Magnoliaceae and thought that the family is relatively specialised from vegetative and reproductive aspects.
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From the stand-point of construction and organisations of flowers, the Magnoliaceae is allied to the Annonaceae.
The two families, however, can be set apart from each other by the following features:
The Magnoliaceae has a great deal of affinity with the gymnosperms. The most striking thing about the wood of Drimys is the presence of tracheids with bordered pits in the xylem. This coniferous nature of the wood is “discounted by the fact that the structure of the bast is characteristically dicotyledonous, having sieve-tubes with companion cells”.
Furthermore, the receptacle of Magnolia flower bears numerous spirally arranged free sporophylls. This can be compared with the strobilus of Bennettites, consisting of a central conical axis covered with megasporophylls. This has led to the suggestion that the order Bennettitales may be ancestral to the modern angiosperms initiated by the Magnoliaceae.
Common plants of the family:
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1. Liriodendron tulipifera L., A large tree with handsome flowers, wood as a timber.
2. Michelia champaca L. “Champa”, A garden plant cultivated for its flowers which are sweet scented; used in perfumery.
3. Michelia grandiflora L. ‘Bari Champa’ or ‘Him Champa” A small tree with fragrant flowers.
4. Magnolia acuminata – Cucumber tree. Largest tree of Magnolias. Its green fruits resemble a cucumber; wood light, soft and durable.
Division of the family and chief genera:
On the basis of the habit, presence or absence of stipules and degree of development of thalamus, the Magnoliaceae is separated into three subfamilies :
Subfamily I. Magnolioideae. Leaves with sheathing stipules. Flowers bisexual. Thalamus long.
Example:
Magnolia.
Subfamily II. Illiciodeae. Leaves with ho stipules. Flowers bisexual or unisexual. Thalamus short.
Example:
Illicium.
Subfamily III. Schisandroideae. Climbing shrub. Leaves with no stipules. Flowers unisexual.
Example:
Schisandra.
