form associations with the roots of broombush species including M. uncinata, M. scalena and M. hamata. The fungus involved is thought to be Thanatephorus gardneri. The flowers of R. gardneri are subterranean but the heads crack open the soil surface as they mature, and sometimes the tips of the bracts protrude through the leaf litter, leaving a small opening through which pollinators may enter. Termites and ants have been seen to enter the flower heads. The orchid's seeds are too large to be dispersed by the wind and it is possible that the succulent fruit is eaten by small mammals and the seeds passed out of their faeces. Conservation status The species is classified as "critically endangered" under the Australian Government Environment Protection and Biodiversity Conservation Act 1999 and as "Threatened Flora (Declared Rare Flora — Extant)" by the Department of Environment and Conservation (Western Australia). Much of the central and southern Wheatbelt of Western Australia has been cleared for agriculture, or affected by drought, resulting in the loss of broombush habitat or a reduction in the level of bark and leaf litter necessary to protect the underground orchid and a reduction in the area suitable for translocation. The main threats to the species include lack of suitable habitat, degraded habitat, drought and rising soil salinity. Three of the known populations of Rhizanthella gardneri are protected within nature reserves, and a concerted initiative has been launched to safeguard this species for future generations. A partnership between the Millennium Seed Bank of the Royal Botanic Gardens, Kew, Australia's Endangered Species Program and Perth's Kings Park and Botanic Gardens are undertaking DNA fingerprinting and seed-banking of this rare orchid in an attempt to establish a propagation programme. References Further reading Reader's Digest Ltd. (1989). Facts and Fallacies - Stories of the Strange and Unusual. Reader's Digest Ltd. Page 39. . Jones, David L. (2006). A complete guide to native orchids of Australia: including the island territories. Frenchs Forest. . gardneri Myco-heterotrophic orchids Orchids of Western Australia Endemic orchids of Australia Plants described in 1928 Taxa named by Richard Sanders Rogers