Wildflowers of Western Australia

A triggerplant has a spring-loaded touch-sensitive column hidden under the petals which flicks over when an insect lands on the flower for a feed of nectar.

At the end of this column is the male and female parts of the flower. (anther and stigma)

This action either deposits or collects pollen depending on the cycle of the plant.

Donkey Triggerplant - Stylidium diuroides

The pollen filled anthers (male) appears first on the young flower, then as it matures the sticky stigma (female) takes over and is ready to collect pollen. This cycle prevents self pollination.

Most of the bees I have seen visiting these flowers have a worn spot on their back where they have been repeatedly whacked by the column.

More bee pics | |

The small lobes in the centre of this beautiful Queen Triggerplant prevents access to the nectar unless the insect lands on the lower petals.

The clever design of the flower forces the insect to land on the same position each time.

Queen Triggerplant - Stylidium affine

These plants are amazingly precise.

To avoid producing hybrids, different species of triggerplants have various shape and lengths of the column, which can strike from under, over or even from the side.

Therefore an insect visiting two species can be struck at different locations on the body.

Circus Triggerplant - Stylidium bulbiferum

These triggerplants strike the insect on the underside of the abdomen like "a punch in the guts".

So named because the flower closes like a book at night or in cold weather.

Book Triggerplant - Stylidium calcaratum

99% of triggerplants have two pairs of petals.

Here you can see 2, 3, 5 and 6 petalled varieties but they are very rare.

Click on the image to see examples. | |

After the column has been triggered it gradually resets, usually within an hour, ready to assault another innocent insect looking for nectar or pollen.

Tangle Triggerplant - Stylidium dielsianum

About 70% of the world's 250+ known species of stylidium occur only in the South-West of Western Australia, highlighting this area as the major center of triggerplant evolution.

Stylidium is the fifth largest genus in Australia.

Click on this image to see the trigger action in more detail.

White Butterfly Triggerplant - Stylidium hispidum

Stylidium are believed to be carnivorous (or protocarnivorous).

It has been reported that the numerous sticky glands on the flowering parts of triggerplants secrete enzymes to trap and digest tiny insects.

If this proves to be true, the addition of this genus would almost double the number of known carnivorous plants.

The largest of all triggerplants and named for the powerful 'kick' when triggered.

These are only 5cm (2in) tip to tip, so most stylidium flowers are very small.

Small children are advised not to touch these flowers.

Cow Kick - Stylidium schoenoides

Class: Gymnospermae

Subclass: Dicotyledonae

Superorder: Asteridae

Order: Campanulales

Family: Stylidiaceae

Pink Fountain Triggerplant - Stylidium brunonianum

The innocence of the flower belies the mamba-shaped head of the column, ready to strike and just as fast.

Click on the image to see this in detail.

Pink Fountain Triggerplant

Boomerang Triggerplant - Stylidium breviscapum

For more detailed information check out the Wikipedia Triggerplant page.

You can trigger the column by lightly touching the centre of the flower with a small stick.

Reed Triggerplant - Stylidium junceum