Trop picks: Flame of the Forest

In 1828, the Austrian botanist Wenzel Bojer "discovered" the Gulmohar or Flame of the Forest (Delonix regia) at Foul Point on the east coast of Madagascar.

He introduced the tree to his European colleagues in the pages of Curtis's Botanical Magazine.

From Madagascar, the tree traveled to Mauritius and several other tropical regions including Singapore, where its presence was first recorded in 1840.

The botanical name of the tree derives from the Greek words delos, meaning “conspicuous,” and onyx, meaning “claw.”

Oddly enough, this massive tree belongs to the same family as the the tiny pea (Fabaceae), and for its survival, it must engage in a delicate dance with the little butterfly. The Delonix is a classic psychophilous species—that is, it is pollinated by butterflies.

The life of the Delonix flower is short and sweet.

Around midnight on the first day, the new flower begins to emerge from the bud. It comes into full bloom by nine in the morning, just in time for the butterflies’ morning rounds. 

The petals are conveniently arranged to provide a landing pad for the butterflies. The largest or standard petal proudly advertises its upper surface, which is white or light bluish and contains red stripes, contrasting with the red lateral petals and red upper surface of the sepals and the red stamen filaments. The colours are a psychophilous adaptation, since butterflies like bright colours like red and yellow. For the same reason, the standard petal has yellow markings to guide butterflies to its store of nectar concealed deep within.

The tubular pathway to the nectar is never longer than the butterfly's proboscis, so the nectar is always within reach. Nectar is most abundant on the first day, slightly less on the second and almost absent thereafter.

By the evening of the first day, the standard petal appears despondent, its ends curled downwards. On the second day, the flower starts to disintegrate, its organs falling off, one by one. Soon, all of the branches of the Delonix are bare, the crimson canopy from the tree above transformed into a velvety carpet on the ground below.

Sources:

www.kew.org

R.W. Cruden and Sharon M. Hermann-Parker in "Butterfly Pollination of Caesalpinia Pulcherrima, with Observations on a Psychophilous Syndrome," Journal of Ecology, 1979.

Peter K. Endress in Diversity and Evolutionary Biology of Tropical Flowers, 1996.