Ptilotus semilanatus is a grass-like plant in the Amaranthaceae family.
Ptilotus semilanatus is endemic to Australia where it is found in Queensland, New South Wales, Victoria, and South Australia.
It was first described in 1848 by John Lindley as Trichinium semilanatum. In 1948 John McConnell Black published Ferdinand von Mueller's description where he had reassigned the species to the genus Ptilotus.