Flowers are often not as obvious in the rainforest as people expect. While many flowers are high up in the canopy, very small, or not all that colourful, there is in fact a wide range of colours and forms. This diversity of forms reflects the wide range of different pollinators in the forests, for the form of a flower reflects it's pollination strategy. Flowers that spread their pollen by wind tend to be small and dull. Those flowers that rely on animals need to have attractive qualities such as pretty colours and nice odours. The animal is then rewarded with sweet water called nectar. The design of most flowers is such that by feeding on the nectar, the animal inadvertently picks up pollen. When they next feed on another flower on another plant, they spread this pollen.
Different plants may try to attract different specific pollinators or vectors. For example, those flowers that are attract birds, will tend to have bright colours such as red, pinks and yellows, such as the Evodia, reflecting the strong sense of sight and weak sense of smell in birds. Those attracting mammals will tend to be duller in colour but with a stronger odour, such as Bumpy Satin-ashes, reflecting the mammal's nocturnal habits and sense of smell. Flowers attracting butterflies and moths are quite different; those attracting butterflies are generally colourful, while those designed for moths are paler in colour and strong in odour, such as the 'Native Gardenia' Randia spp.
However, some animals are not playing the game and rather than being satisfied with protein poor nectar, want to steal the much richer pollen. Many bees will actually cut into the side of a stamen to drill out the pollen. However, some plants still manage to get the pollen thieves to act as pollinators. In the flowers of the melastomids, (commonly seen on the side of tracks in the wet tropics, right), the purple flowers actually have two sets of stamens. The brighter contrasting yellow stamens in the middle produce a 'cheap' pollen, while the real pollen is in the duller purple stamen on the outside that even pollen thieves have to climb over (and thus inadvertently collect) to get to the 'fake' stamens. If a flower is successfully fertilized, a seed starts to develop. In the flowering plants, this seed is wrapped in a covering called the fruit, and this has evolved to disperse that seed inside.
One of there most famous ecological relationships is that between their flowers and fig wasps. These tiny flowers of each particular species of fig are pollinated only by another particular species of 'fig wasp' (family Agaonidae). The plant relies on the wasps for pollination, while the wasps rely on the 'fruit' to reproduce within. Because of this relationship, it is thought figs have to provide these fruit receptacles more or less continuously, and thus many figs fruit asynchronously. That is, trees fruit out of sync with other individuals of the same species.