Friday, 25 January 2008
Though I would have liked to discuss about related families every week, Some theme has to be selected that is the reason why I am going alphabetically. It may look little odd as the families in consecutive weeks may not have any relation with each other.
This week's family is
Widely distributed in tropics.Common examples are Annona squamosa,Polyalthia longifolia and Artobotrys odoratissimus.
Vegetative characters:Usually aromatic trees or shrubs,or sometimes woody climbers.
The leaves are alternate exstipulete,simple and entire.Oil passages are present in stems as well as leaves.
The flowers are often solitary,axillary terminal or leaf opposed or sometimes fascicled.
The flowers are mostly bisexual actinomorphic and hypogynous.
The perianth is usually trimerous and differentiated into calyx and corolla.There are three sepals and usually six petals in two whorls.Androecium has numerous stamens spirally arranged on alrge convex receptacle and the gynoecium has one to indefinite carpels which are spirally arranged on the receptacle above the stamens.The carpels are free but very rarely,as in Annona, they are subconnate with distinct stigmas. The ovary is superior,unilocular with usually many anatropous ovules in two rows on the ventral suture of the carpel.
The fruit is often an aggregrate of berries.Many seeded berries are usually constricted between the individual seeds.In annona the berries become confluent with each other and with the receptacle to form a globose or ovoid many seeded freshy fruit.The seeds are large with a small embryo.
Flowers are often fragrant due to oil sacs and are pollinated by flies.
In most Annonaceae the mature carpels are juicy and coloured and are freely eaten by birds and bats.Annona which has compact fleshy fruit, too big to be carried by birds is generally dispersed by mammals.Th seeds of Artabotrys and polyalthia are drifted by sea.
Many species yield edible fruits: Annona squamosa(Custard apple),A.reticulata(Common Custard apple),Canaga odorata.
Some species are grown as ornamentals:
Artabotrys odoratissimus(Climbing Ylang Ylang)
Polyalthis longifolia and pendula(Ashoka)One of the most beautiful avenue trees.
Flowers of Canaga odorata and Artabotrys odoratissimus yield an essential oil which is used in high class perfumery and toilet preparations.
The leaves of trees of Annonaceae are larval host plants of Tailed jay butterflies so these butterflies are abundant in gardens with these trees.
Posted by SATISFIED at 23:12