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Wednesday, 4 February 2009

FAMILY OF THE WEEK: STERCULIACEAE


Sterculia foetida



Firminia colorata


Eriolaena quinquelocularis


Sterculia alata


Gauzuma


Dombeya


Pterospermum acerifolium

FAMILY OF THE WEEK: STERCULIACEAE

Family chiefly of tropics. There are 18 genera and more than 90 species mostly in tropical areas while some are in Himalayas.
Vegetative characters:
Mostly soft wooded trees or shrubs, sometimes herbs, rarely climbers. The younger parts are often stellate, tomentose. The bark is mucilaginous and the inner often fibrous. The leaves are alternate or rarely subopposite, simple, entire, palmately lobed or digitate(Sterculia). The petiole is often pulvinate. Stipules present usually caducous.
Inflorescence and flowers:
Inflorescences are axillary or sometimes terminal complex cymes. The flowers are hermaphrodite or unisexual or polygamous, actinomorphic, pentamerous and hypogynous. The calyx has five sepals, valvate more or less united, often coloured(Sterculia).Corolla has five petals. They are absent in Sterculia, free or adnate to the base of the staminal tube. They are deciduous or sometimes persistent(Dombeya). Androecium has few to many stamens which are free or often connate in tube. Gynoecium is 2-5 carpellary and syncarpous with a superior ovary, sessile or raised with androgynophore. The style is simple or lobed or rarely divided upto the base
Fruits and seeds:
Fruits are dry / fleshy, dehiscent/indehiscent. Seeds endo/nonendospermic with a straight or a curved embryo.
he seeds are numerous, compressed, discoid or subreniform, endospermic and with a curved or straight embryo.
Pollination and dispersal:
Pollination is by insects. Winged seeds of Dombeya and Pterospermum favor wind dipersal of seeds. It also takes place by animals and birds.
Examples:
Sterculia Pterospermum
Helicterus

Dombeya

Theobroma cacao
(Coco tree)
Cola acuminata
Gauzuma ulmifolia

Firminia colorata
Eriolaena quinquelocularis

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