This species of terrestrial bladderwort has an Autralasian range. It is among the seven species of Utricularia described by Linnaeus in 1753, this one from a Type specimen from China. The species epithet possibly refers to the two-cleft, fang-like appendages near the trap mouth. These are sensor trichomes that are essential for the trap to detect prey that has come within “striking range”. When the trichomes are triggered by small prey such as a protozoan, the trap door opens and the prey is sucked in within a fraction of a second.

This is by far the most common terrestrial Utricularia in Peninsular Malaysia. It can be found on damp or waterlogged soil or sand from the lowland to the lower montane forest. It was recorded by Ridley to occur in rice fields in the early twentieth century. The species, however, has not been found in this habitat from recent field observations. This could be a result of intensive farming that involves the use of chemical fertilizers and pesticides, to which bladderworts in general are known to be sensitive.

The species often occurs side by side with the other bladderworts, especially U. minutissima. Their minute and delicate stolons and leaves are often intertwined, making the task of separating them near impossible. The leaves of Utricularia are often variable in size and sometimes even in shape. As a result, it is difficult to tell the species apart when not in flower, unless the minute, subterranean traps are removed carefully and examined under high magnification. The diversity of trap appendages among species is a good taxonomic characteristic to tell the species apart. Unfortunately, collectors often only pick out the more conspicuous inflorescence or infructescence with a little bit of rhizoid or stolon attached but fail to collect the traps.

U. bifida is a yellow flowering Utricularia. The corolla, as in all other bladderworts, is intricately designed. The conical and downward pointing spur is easily recognizable. The calyx is persistent in fruits, turning an attractive maroon and enlarging to totally enclose the capsule within. The seeds are about half a millimeter long and obliquely obovoid, their testa cells have raised boundaries and are arranged along the longitudinally sinuate axis. With a bit of imagination, the seeds resemble tiny chocolate candies encased in twisted wrappers.

So far no pollinator is known, although a large number of thrips has been observed in flowers of a gregarious population. The stigma has a semicircular lower lip which, in the later stages of a fully opened flower or a cleistogamous (non-opening) flower, bends downward to touch the anthers beneath, suggesting that self-pollination is possible and could even be the norm.

By Chew Ming Yee
e-mail: chew@frim.gov.my