Flower of fried-egg

CHENNAI : Everyone might have experienced the sharp pain from a spiny plant at least once in their lifetime. It may have been while nipping beautiful roses from prickly stems or while grabbing the juicy fruits of lemon, pomegranate and so on! And everyone who was pricked might have questioned, “Why do these plants have thorns?”

Since plants are typically anchored,  they have developed thorns as a defence mechanism against predators. Besides this, there is also an interesting evolutionary pressure on the immovable plant community, which resulted in the progressive development of thorns. It is speculated that originally thorns were inconspicuous, relatively insignificant and could dissuade common insects and other small animals from eating the plants.

The enlarged protective system of thorns came into existence simultaneously with the evolution of larger grazing animals and humans. Therefore, the type of thorns in plants also indicate the amount of pressure from predators. 

A species that possesses a highly evolved system of thorns is Oncoba spinosa Forssk, belonging to the family Flacourtiaceae. This species has unusual, forked and very strong bunches of thorns. It normally grows in open dry lands, woodlands or savanna. The look of the thorns itself can threaten predators.

O. spinosa is a shrub or small tree that reaches up to 8 m tall and has a greyish-brown  bark with irregular flakes. Leaves are on short stalks, 6–10 cm long and 3-6 cm broad, with margins toothed. Flowers are terminal, solitary, 5-8 cm across, sweet-scented and the five-12 white petals white are denticulate.

It has numerous bright yellow stamens and an outer circle of white petals with a glossy yellow mass of anthers at the centre, which mimics fried egg, hence the popular name ‘fried-egg’ flower! The fruits are spherical, up to 4-6 cm across, green when young and  reddish-brown when matured. The pulp of the fruit is said to be edible and its leaves and seeds are used in treating fever, leprosy, skin problems, diarrhoea and dysentery.