Levenhookia stipitata Common Stylewort Endemic
Levenhookia species are related to Stylidium (Trigger Plants) and have a pollination mechanism which also involves fast moving flower parts distributing pollen.
The flower has four obvious pinks petals but also a white structure called a labellum (the fifth petal) which has a sensitive blob on the end.
From the centre of the flower grows an erect column called a gynostemium on top of which there are anthers containing pollen. The gynostemium tries to grow tall but is restrained by flaps on the labellum enclosing it. It starts to curve under the strain of trying to grow erect but is prevented by the enclosing flaps of the labellum. An insect coming to sip nectar from the flower inevitably touches the sensitive blob on the end of the labellum which causes the flaps to open suddenly. This releases the gynostemium from its prison and shoots quickly from a bent into an upright position. There is a bucket shaped structure (nectary bucket) also in the centre which causes the moving gynostemium to come to a sudden halt. The kinetic energy of this flick to an upright position causes the now ripe pollen in the anthers on the end of the gynostemium to be propelled towards the underside of the insect where the pollen grains stick and are ready to be flown by the insect to another flower effecting cross pollination.
Of course this indiscriminate splattering of pollen could also fertilise nearby flowers on the same plant but not enough work has been done on these plants to give details of how much seed arises from cross pollination and how much from self pollination.
When the pollen has been released the gynostemium is now erect and a stigma grows from the top above the spent anthers.
In true Trigger Plants (Stylidium sp) the trigger is reset and can be triggered again but in Levenhookia the rapid "flick" movement happens only once. The mechanism has been likened to flicking a blob of inky paper across a school room with a ruler (which rather assumes the reader knows what ink and ruler mean - try Google).
Levenhookia species were named by Robert Brown (1773 to 1858) after Antonius van Leeuwenhoek whose work on microscopes was very important in his day.
Levenhookia stipitata is the commonest of the Styleworts and grows dotted about from Geraldton, commonly around Perth, into the Wheat belt and even down to Esperance.
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| Levenhookia stipitata Common Stylewort gynostemium not released from labellum | Levenhookia stipitata Common Stylewort after insect has visited |
Bushland near Donnelly Mill Rd., Yornup, Western Australia
Added on December 12th 2013