Rhizanthella gardneri is a cool growing terrestrial orchid from the genus Rhizanthella.
The plant blooms in May and June and measures 2.5–3 cm. The flower head contains 8 to 90 small dark maroon flowers.
The white leafless plant is made up of a tube which produces a flowerhead. Unlike any other orchid in Australia, the Western Australian underground orchid remains completely underground for its whole life. Not being able to obtain the sun's energy, it instead feeds on the broom honey myrtle, a shrub. It is linked to it by a fungus named Thanatephorus gardneri.
The plant was discovered in the spring of 1928 when Jack Trott had bent to investigate an odd crack that had appeared in his garden's soil, and had noticed a sweet smell that arose from the ground. Scraping away the soil, he soon uncovered a tiny white flower, about half an inch across, growing underground. What he had found was an entirely new type of orchid.
This particular orchid is a myco-heterotroph as it relies completely on the Melaleuca uncinata and a mycorrhiza fungus for its nutrients and carbon dioxide. Having received this from the fungus the plant is then able to convert the water, nutrients and carbon dioxide into the energy needed for growth and maintenance.
Rhizanthella gardneri reproduces vegetatively by which it can produce three daughter plants, as well as sexually. In the latter case the pollinated flower will then take six months to mature - pollination is thought to be effected by some animal species attracted by the fragrance. The seed is thought to be dispersed by Marsupialia, who eat the fruit, but substantial findings are hard to come by as only 19 mature specimens of the orchid are known to currently exist in the wild and only 300 specimens have been collected to date.
Plant is found in the sandy dry soil of Western Australia at elevations of 300 to 400 meters
Plant grows in cool conditions.
Common Names: Gardner's Rhizanthella