Habenaria harroldii, commonly known as the southern rein orchid, is a species of orchid that is endemic to the Fraser Coast region of Queensland. It has up to five leaves at its base and up to twenty five white flowers with reduced side lobes on the labellum.
Habenaria harroldii is a tuberous, perennial herb with between three and five upright, dark green leaves at its base, the leaves NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide. Between three and twenty five lightly scented white flowers, NaNsigfig=2NaNsigfig=2 long and NaNsigfig=1NaNsigfig=1 wide are borne on a flowering stem NaNsigfig=1NaNsigfig=1 tall. The dorsal sepal is NaNsigfig=2NaNsigfig=2 long and about 5sigfig=1NaNsigfig=1 wide, overlapping with the base of the petals to form a hood over the column. The lateral sepals are NaNsigfig=1NaNsigfig=1 long, about 5sigfig=1NaNsigfig=1 wide and spread widely apart from each other. The petals are NaNsigfig=1NaNsigfig=1 long and about 4sigfig=1NaNsigfig=1 wide. The labellum is NaNsigfig=1NaNsigfig=1 long, about 5sigfig=2NaNsigfig=2 wide and usually undivided. The nectary spur is NaNsigfig=1NaNsigfig=1 long and more or less straight. Flowering occurs from January to March.[1]
Habenaria harroldii was first formally described in 1998 by David Jones from a specimen collected near Tewantin and the description was published in The Orchadian.[2] The specific epithet (harroldii) honours Arthur George Harrold who collected the type specimen.[3]
The southern rein grows with low shrubs and grasses in woodland between Tewantin and Maaroom.