Pollination In a flowering plant fertilisation actually occurs in the ovary, but the pollen has to be transferred to the female part of the plant by wind or a variety of living agents like insects, small mammals and birds. The process of the pollen reaching the sticky surface of the stigma of the female part of a plant is called pollination.
Living pollinating agents are attracted to the flower by its smell, colour, shape and availability of a food source, especially nectar, but also the pollen itself. As an insect, small mammal or bird brushes past the anther it picks up pollen and deposits it when it touches a stigma.
In most species the pollen is produced at a different time than when the stigma can receive it, so that plants are not usually pollinated by their own pollen (self pollination). In most instances flowers are pollinated with pollen from other plants of the same species (cross pollination).
This insures greater variation in the offspring.Bees are perhaps the most recognised pollinating agent, carrying pollen from one flower to another as they seek out nectar, from which they produce honey.
However, many Australian flowers are also pollinated by birds, especially the honeyeaters (eg. wattle birds, noisy miners, spinebills), and by small mammals like the pygmy possums, some of the marsupial mice (more correctly called marsupial carnivores or insectivores, like the various species of Antechinus).
There is even a tiny marsupial called the honey possum which pollinates flowers in Western Australia where it is found. Common species found in the bush and in gardens throughout Australia are pollinated by these vertebrate species, including many of the bottlebrush (Callistemon), Banksia and Grevillea species.
Many of these pollinating species have brush-tipped tongues for penetrating the flowers to gather nectar. Pygmy possums weighing only around 24 grams, feed mainly on nectar and pollen, but will also take insects in their diet.Wind is responsible for pollinating many Australian plant species, especially the grasses.
In these species the anthers are very long and produce large amounts of light pollen, which is easily picked up by the wind passing over the flowers. Usually the stigmas are also very large and spread out to receive pollen carried by the wind.
Banksia This banksia has started to release the styles from the top of the inflorescence. Notice the bee is visiting the opened flowers.
Banksias are a member of the Proteaceae family which is a Gondwanan group of plants. Their distinctive flowers (spikes) consist of thousands of individual flowers grouped together in an inflorescence. The grouping of flowers gives a rich reward to any pollinator that visits and provides a large flower that is easy to find.
The flowers are often seen dripping with nectar and this acts an attractant to insects and birds. The flower first appears as a solid cylinder and starts to open usually from the top. In Banksia ericifolia there are four anthers and a hooked style. At first the style is hooked underneath the stamens. The male parts of the flowers mature at first and are then released. This prevents self-fertilisation from occurring.
Grevillea • Grevilleas are another member of the Proteaceae family. The flower consists of an inflorescence with many individual flowers grouped together as an attractant to pollinators.
Lambertia formosa • Lambertia formosa is a bird pollinated flower Each individual flower has female and male parts. There is a nectar reward offered for birds with beaks long enough to get to the end of the floral tube.