Ptilotus rotundatus is a species of flowering plant of the family Amaranthaceae and is endemic to the Top End of the Northern Territory, Australia. It is an annual herb with linear to lance-shaped stem leaves, up to 40 spikes of whitish flowers and spherical, reddish brown seeds.
Description Ptilotus rotundatus is an annual herb that typically grows to a height of , its stems, branches and foliage covered with whitish, rough, curved, soft hairs. The stem leaves are arranged alternately, linear to lance-shaped tapering on both ends, long and up to wide, with a prominent midrib on the lower surface. The flowers are borne in up to 40 oval to conical spikes up to long and wide with up to 30 to 40 whitish flowers on the ends of branches. The many oblong to egg-shaped bracts are mostly long and wide and the bracteoles long and wide. The outer tepals are long, and there are five stamens. The style is straight, about long and the ovary is conical, long and wide. The seeds are spherical amd reddish brown.
Taxonomy Ptilotus rotundatus was first formally described in 1984 by Gerhard Benl in the journal Muelleria from specimens collected near Boggy Plain Creek near Jabiru in 1973. The specific epithet (rotundatus) means 'rotund', referring to the outer tepals.
Distribution and habitat This species of Ptilotus is only known from the Arnhem Plateau, Darwin Coastal and Pine Creek bioregions in the Top End of the Northern Territory.
Conservation status Ptilotus rotundatus is listed as data deficient under the Territory Parks and Wildlife Conservation Act.
References