Friday, December 16, 2016

Confessions of a Nibbler: The Story of the Inside-Out Flower

Ficus carica ‘Brown Turkey.’
By Sara SmithDurham Co. Extension Master Gardener

The professor and I finished dinner and I asked, “Do you want some dessert?”  “Sure!” he says, and we head out the door; not to a restaurant or ice cream parlor, but to our side yard where the dessert tree, Ficus carica ‘Brown Turkey’, stands; its branches are laden with sweet flower clusters. Ah figs, my favorite edible flowers. Yes, flowers. What we call the “fruit” of the fig is actually a swollen stem called a synconium that contains a cluster of inflorescent flowers. Break one open and you can quickly see the strange looking tiny flowers. Even though they look rather odd, they have all the same parts as flowers that bloom on the outside of the stem.

You may have heard of the special relationship that the fig has to its pollinator, the fig wasp Blastophaga psenes. When the synconium is full of flowers that are ready to be pollinated, the tree sends out “come hither” chemicals to attract a pregnant female wasp. A tiny hole opens up to allow the wasp in. The opening is so small that she usually loses her wings and antennae during the entry. Once inside, she pollinates the stigmas and lays her eggs in the ovules of some of the florets. Having done her duty, she dies. Don’t worry. You won’t eat her. She is fully absorbed before the “fruit” is ripe.

When the eggs hatch, the larva feed on the endosperm tissue of the galled ovary. At maturity, the males and females mate and the males chew a hole through the wall allowing the pollen-carrying pregnant females to escape and the cycle begins again. Now that the flowers are pollinated, the fig ripens and the tree changes its chemical call to attract fruit eating birds and animals (like me!)

The relationship between the fig and its pollinator is one of the best examples of coevolution, but it all sounds so chancy. What if we don’t have any fig wasps in our neighborhood? Lucky for us, the cultivars that grow best in our area do not require the wasp in order to fully produce. Figs are divided into four varieties; the caprifig, the Smyrna fig, the San Pedro fig and the common fig. The caprifig has male and female flowers and requires the wasp for pollination. The Smyrna fig needs to be cross-pollinated with the caprifig. The San Pedro fig is an intermediate, meaning that its first crop in the spring doesn’t need pollination, but it’s second crop in the fall does. The common fig has all female flowers and doesn’t need to be pollinated in order to fully develop, although it will not produce seed. Common fig cultivars include ‘Black Mission’, ‘Brown Turkey’, ‘Brunswick’, and ‘Celeste’.

Figs produce two crops each year; one in the spring called the breba crop that develops on last season’s growth and the main one in the fall that develops on the current year’s growth. The branches holding the spring crop may die back in our winters, but don’t despair. The fall crop soon ripens producing delicious gooey packets of sugary inflorescences to delight nibblers of all species. 

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