Diuris byronensis, commonly known as the Byron Bay donkey orchid, is a species of orchid that is endemic to the Arakwal National Park in New South Wales. It has one or two grass-like leaves and up to five bright yellow flowers with blackish markings. It has a very limited distribution near Byron Bay.
Diuris byronensis is a tuberous, perennial herb with one or two leaves NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide and folded lengthwise. Between two and five bright yellow flowers with blackish markings, NaNsigfig=1NaNsigfig=1 wide are borne on a flowering stem NaNsigfig=1NaNsigfig=1 tall. The dorsal sepal is more or less erect, NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. The lateral sepals are NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide and turned downwards. The petals are held horizontally, often turned backwards with an elliptic blade NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide on a brown stalk NaNsigfig=2NaNsigfig=2 long. The labellum is NaNsigfig=1NaNsigfig=1 long and has three lobes. The centre lobe is egg-shaped, NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide and the side lobes are NaNsigfig=1NaNsigfig=1 long and less than 1sigfig=1NaNsigfig=1 wide. There are two ridge-shaped calli 3sigfig=1NaNsigfig=1 long at the base of the mid-line of the labellum. Flowering occurs in August and September.[1]
Diuris byronensis was first formally described in 2003 by David Jones from a specimen collected near Byron Bay and the description was published in The Orchadian.[2]
The Byron Bay donkey orchid is only known from a small part of the Arakwal National Park where it grows with sedges and grasses in a rare type of heath known as Byron Bay Dwarf Graminoid Clay Heath.[3]
Diuris byronensis is classed as "critically endangered" in the IUCN Red List of Threatened Species and as "endangered" under the New South Wales Biodiversity Conservation Act. The main threats to the species are its limited geographic range, loss of habitat and weed invasion. Projects are underway to protect the habitat of this orchid and other threatened species.