Sunday, 20 April 2008
30-200 genara and around 200 species.
The family is almost restricted exclusively to the drier regions of north and south America and is most abundant in Mexico and central America.
Several species of Opuntias have been naturalised in India.
Vegetative characters :
The members of the family are mostly fleshy and succulent, and some grow upto 20 meters high.
The root system is generally small and shallow with elongated slender and fleshy roots.
Cactus stems are fleshy,peculiar and of various shapes. The leaves are alternate, generally extremely reduced and ephemeral or absent, or rarely they are well developed and fleshy. The leaves are associated with highly modified axillary buds or shoots called areoles that bear spines.
The inflorescence is a terminal or lateral panicle in Pereskia but in majority the flowers are solitary born upon or near the areole or on the axiles of tubercles.
The flowers are sessile often large bright coloured and showy, mostly bisexual and actinomorphic and commonly have many weakly differentiated perianth segments arising from an epigynous zone.
The androecium typically consists of a very large number of stamens arising from the inner face of the epigynous zone.
The gynoecium consists of a compound pistil of 3-many carpels, an equal number of stigmas, and an equal number of parietal placentae with numerous ovules in the single locule of the inferior ovary.
The fruit is a berry with numerous seeds, often with spines or bristles.
Large showy flowers are adapted for insect pollination.
Fruits are sweet in taste and are often distributed by animals.
Examples and Uses:
The fruits of several species of opuntias are edible.
Species of opuntias Nopalaea etc are used for hedges along the fields.
Cochineal dye is derived from the small insect living on the species of Opuntias and Nopalaea.
Timber is obtained from Pereskia.
Spineless opuntia is grown as fodder.
Because of their peculiar forms and gorgeous flowers several species of Mammilaria,Epiphyllum,Cereus,Echinocereus are grown in green houses.
Epiphyllum oxypetalum -ब्र्म्हकमळ
Posted by SATISFIED at 11:14