Carica papaya.
There are 5 or 6 Carica genera and around 35 species.
Carica papaya is commonly known as the Pawpaw or papaya fruit.
All parts of the plant contain latex and the enzyme papain has numerous commercial uses.
The papaya is a herb with a hollow trunk that is only slightly woody.
It is a small, usually unbranched tree that grows up to 10 m high.
Its leaves are confined to the top of the tree and the trunk has marked leaf scars.
The leaves are alternately arranged in a spiral.
The petiole is to 100 cm long and the blade up to 70 cm across.
The blade is deeply divided into 7 lobes in a palmate fashion.
The plant bears flowers and fruit throughout the year.
Male and female flowers typically occur on separate trees but cultivars have both male
and female flowers on the same tree.
The cream, trumpet-shaped flowers grow in the leaf axils.
Female flowers are solitary or in small clusters.
The males are on long stalks with many flowers.
The calyx has 5 small sepals fused at the base.
The corolla has 5 petals fused into a narrow tube that ends in 5 flared, blunt lobes.
The male flowers have longer tubes than the female.
The lobes are often twisted.
Male flowers have 10 stamens in 2 whorls attached to the top of the corolla tube.
One whorl has longer stamens than the other.
The introrse anthers dehisce via longitudinal slits.
Flowers are only open for 1 day.
The ovary is absent or greatly reduced and there are nectaries.
Female flowers have a superior ovary and no nectaries.
There are 5 carpels and styles but only one locule in the ovary.
Female flowers remain open for 7 days.
Papaya fruits are berries with clusters of them attached to the trunk just below the leaves.
There are a number of cultivars bred for their different size, shape and flesh colour.
Commercial fruits are about 15 cm long and 1 Kg in weight.
Shapes include round or oval fruit (from female flowers) and club or pear-shaped ones
(from hermaphrodite plants).
Fruits have a smooth skin that ripens from green to yellowish.
The abundant flesh ripens to a yellow or reddish colour depending on the variety.
In the centre is a round or star-shaped cavity filled with small, round black seeds.
J.F.
