Genoplesium anthracinum, commonly known as the black midge orchid, is a species of small terrestrial orchid endemic to New South Wales. It has a single thin leaf fused to the flowering stem and up to thirty small, coal black flowers. It grows in heath in coastal and near-coastal parts of the Northern Rivers area.
Genoplesium anthracinum is a terrestrial, perennial, deciduous, herb with an underground tuber and a single thin leaf NaNsigfig=1NaNsigfig=1 long and fused to the flowering stem with the free part NaNsigfig=1NaNsigfig=1 long. Between eight and thirty coal black flowers are arranged along a flowering stem NaNsigfig=1NaNsigfig=1 tall and taller than the leaf. The flowers are about 4sigfig=1NaNsigfig=1 long and 5sigfig=1NaNsigfig=1 wide and are inverted so that the labellum is above the column rather than below it. The dorsal sepal is about 4sigfig=2NaNsigfig=2 long and 3.5sigfig=1NaNsigfig=1 wide with hairless edges. The lateral sepals are about 6sigfig=1NaNsigfig=1 long, 1.5sigfig=1NaNsigfig=1 wide, have a prominent gland on the pointed tip and spread widely apart from each other. The petals are about 2.5sigfig=1NaNsigfig=1 long, 1sigfig=1NaNsigfig=1 wide with hairless edges and spread widely apart from each other. The labellum is about 2.5sigfig=1NaNsigfig=1 long, 1sigfig=1NaNsigfig=1 wide, with an irregular margin and a sharply pointed tip. There is a callus in the centre of the labellum and extending nearly to its tip. Flowering occurs in April and May.[1] [2]
The black midge orchid was first formally described in 2006 by David Jones who gave it the name Corunastylis anthracina and published the description in Australian Orchid Research.[3] In 2014, Julian Shaw changed the name to Genoplesium anthracinum.[4] The specific epithet (anthracinum) means "coal black".[5]
Genoplesium anthracinum grows in heath, often colonising disturbed sites and is found between Byron Bay and Wardell.