Cost but no effect, the Bat Lily

The Bat Lily (Tacca integrifolia) is a rather inconspicuous understorey herb common along the trails of Bukit Timah Hill. However, the same cannot be said for its inflorescence. Bat-wings like bracts are erected above the flowers and showy bracteoles hang down resembling the whiskers of a cat.



Since seeing this pretty flower in Feb this year, I have wondered what kind of animal pollinates for this plant. A random search in the net revealed a rather surprising discovery.



A study conducted on a similar species, Tacca chantrieri is actually a highly selfing plant. It was previously thought that Tacca species were cross pollinated by flies, due to its dull colours and musky odur; a phenomenon known as sapromyiophily.

However, several attributes including the low pollen to ovule ratio and the close proximity of anther and stigma gave evidence that they are predominantly self pollinated. Experimental removal of their extravagant displays also have no distinct effect on fruiting, indicating that such structures might be a result of a relict syndrome; meaning something that is of use in the past but with no functional significance now.