Overview
The Tall Donkey Orchid (Diuris drummondii) is a towering, magnificent terrestrial orchid endemic to southwest Western Australia. Standing up to a meter in height, it is the tallest member of the donkey orchid genus *Diuris*. Inhabiting deep winter-wet peat swamps and paperbark flats, it blooms in late spring and early summer after seasonal standing water has evaporated, presenting a stunning floral spectacle.
Biology and Physical Characteristics
Diuris drummondii produces a tuft of three to six long, narrow, grass-like green leaves that emerge through surrounding wetland sedges. In late spring (November to January), a sturdy, erect green stem arises, carrying between two and eight large, brilliant yellow flowers marked with bold brown-maroon blotches. The dorsal sepal is broad and erect, while the two upper petals project upwards like the ears of a donkey. The labellum is three-lobed with a broad, flat, fan-shaped yellow central lobe.
Behavior and Ecology
The Tall Donkey Orchid is a classic floral mimic, engaging in generalized food deception. Its vibrant yellow and brown flowers visually imitate sympatric native pea flowers (Fabaceae), such as *Daviesia* and *Pultenaea*, tricking native bees into visiting the flowers in search of nectar and pollen. By flowering late into early summer when other terrestrial orchids have dried up, it captures the undivided attention of active summer pollinators.
Conservation and Human Impact
Federally listed as Vulnerable under the EPBC Act, Diuris drummondii has suffered substantial declines across the Swan Coastal Plain due to urban development, draining of peat wetlands, and peat extraction. Surviving populations are concentrated in protected nature reserves and regional parks between Perth and Walpole, where seasonal hydrology remains intact and fire regimes are monitored.
Interesting Factoid
Named in honor of James Drummond, the premier colonial botanist of Western Australia who collected extensively across the state in the 1830s and 1840s, this orchid can stand over three feet tall, easily rising above dense wetland rushes.
Last updated: October 2026