Rhizanthella gardneri - this is a highly enigmatic plant that spends all its life below the ground and is endemic to western Australia. It consists of a fleshy underground storage stem, which produces a flower head consisting of around 150 tightly packed, tiny flowers. Underground insects such as termites and gnats pollinate the flowers. It is thought that the native marsupials were important for seed dispersal. This orchid is always found in association with the root system of broom honey myrtle, which obtains nutrients from the orchid. Only 6 populations of this species are known, all of which are near the coast. Large areas of bushland have been developed for agriculture and this has contributed to the decline of this plant. Further threats include drought, the encroachment of salt and decline of the broom honey myrtle.