#ThreatenedSpecies of the Week – Caladenia drakeoides (Hinged Dragon Orchid)

3Caladenia drakeoides, also known as Hinged Dragon Orchid, is listed as Endangered under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and as Declared Rare Flora under the Wildlife Conservation Act 1950.

The main threats to Caladenia drakeoides are inappropriate fire regimes, rising saline water tables, grazing, degraded habitat, weeds, poor recruitment and limited genetic diversity.

Caladenia drakeoides is an inconspicuous, erect, 20-30 cm tall tuberous herb. Usually single, or rarely two flowered, it differs from other Caladenia species in its small hanging petals and sepals (13-17 mm by 2.5-4 mm), its small hinged labellum (5-7 mm long) with two lateral slight swellings (not antenna-like as in the related C. barbarossa), and its hump like shoulder calli. The latter are 1.5-2 mm wide, golden brown with small dark red spots, with a cranial depression and two lateral anterior slight swellings.

On rare occasions C. drakeoides hybridizes with Caladenia exilis and Caladenia longicauda, and these have been named x Caladenia ornata and x Caladenia enigma respectively.

 Caladenia drakeoides has an insect-like labellum which emits a pheromone similar to that of a female thynnid wasp. Male thynnid wasps attempt copulation with the labellum and in the process remove or deposit pollen. Like other orchids, C. drakeoides produces thousands of tiny seeds that contain little testa. These seeds rely on a symbiotic association with soil fungi for germination.

Caladenia drakeoides is confined to seasonally moist rises above salt lakes between Coorow, Beacon and Goomalling. Habitat is tall to medium shrubland dominated by Melaleuca and Acacia species over low shrubs and annuals. Soils are variable but consist mainly of grey sandy loam.

Information Source: Government of Australia, Department of Environment and Department of Parks and Wildlife Western Australia.

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