Diuris unica is a species of orchid which is endemic to eastern Australia. It usually has only one grass-like leaf at its base and up to eight bright, lemon-yellow flowers with a few dark markings. It is similar to D. chrysantha but flowers much earlier than that species and has only a single leaf rather than two.
Diuris unica is a tuberous, perennial herb with a single, linear leaf, NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide and folded lengthwise. Up to eight flowers NaNsigfig=1NaNsigfig=1 wide are borne on a flowering stem NaNsigfig=1NaNsigfig=1 tall. The flowers are bright lemon-yellow with a few dark markings at the base of the dorsal sepal and labellum. The dorsal sepal curves upwards and is egg-shaped, NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. The lateral sepals are egg-shaped to spatula-shaped with the narrower end towards the base, NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide, held below the horizontal and parallel to each other or crossed. The petals are erect with an elliptical to almost round blade, NaNsigfig=1NaNsigfig=1 long and wide on a blackish stalk NaNsigfig=2NaNsigfig=2 long. The labellum is NaNsigfig=1NaNsigfig=1 long and has three lobes. The centre lobe is egg-shaped to wedge-shaped, NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide and the side lobes are oblong to broadly wedge-shaped, NaNsigfig=1NaNsigfig=1 long and about 2sigfig=1NaNsigfig=1 wide. There are two thick, ridge-like calli NaNsigfig=2NaNsigfig=2 long in the mid-line of the base of the labellum. Flowering occurs from July to September.[1]
Diuris unica was first formally described in 2006 by David Jones from a specimen he collected near Maryborough in 1986.[2] The specific epithet (unica) is a Latin word meaning "only", "sole" or "singular",[3] referring to the single leaf of this orchid.
This orchid grows in wallum and sandy heath in coastal and near-coastal districts in south-eastern Queensland and disjunctly in northern New South Wales.