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Saturday, 11 October 2008

MYRTACEAE


Syzigium cumini

Eucalyptus sp.

Callistemon


Psidium guajava (Guava,Amrood,Peru)


Syzygium (Jamun,Jambhul)

FAMILY OF THE WEEK :MYRTACEAE
A large family of 120 genera and 3375 species worldwide. In India there are 14 genera and 165 species occurring chiefly in Eastern India.
Vegetative characters :
Trees or shrubs with aromatic fragrance.
The vascular bundles in the stem are bicollateral and oil glands are present in young stem leaves and floral parts.The leaves are opposite or rarely alternate or crowded at the ends of branches, simple persistent, thick,mostly entire and exstipulate.
Inflorescence and flowers :
The flowers are axillary solitary(Psidium), in racemes (Barringtonia),in heads or spikes(Callistemon) or in cymes(Tristania).
The flowers are bracteate and often have two bracteoles at the base. They are hermaphrodite, actinomorphic,four or five merous, epigynous. The calyx is composed of four or five sepals. The corolla is of five petals. Mostly the stamens are numerous, free, or united into bundles opposite the petals. The gynoecium is two to several carpellary syncarpous and with an inferior ovary having as many locules as the number of carpels. The style is one smooth or bearded at the summit and the stigma is simple. The ovary is crowned by a fleshy disc.
Fruits and seeds :
The fruit is loculicidally or septicidally dehiscent or sometimes indehiscent woody or fibrous or a fleshy berry.
Pollination and seed dispersal :
The flowers are pollinated by insects which visit for nectar secreted by the fleshy disc crowning the ovary.Species like Callistemon are pollinated by birds.The dispersal of seeds takes place by wind or by birds and animals.
Examples :
Eucalyptus (Nilgiri)
Syzygium (Jamun,Jambhul)
Psidium guajava (Guava,Amrood,Peru)
Pimenta officinalis (Allspice)
Callistemon Myrtus communis.

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