Pityrodia chrysocalyx is a flowering plant in the mint family Lamiaceae and is endemic to the south-west of Western Australia. It is an erect, bushy shrub with small, glossy leaves, and flowers with white petals and a golden-yellow calyx.
Pityrodia chrysocalyx is an erect, bushy, compact shrub which grows to a height of NaNsigfig=1NaNsigfig=1 with its branches densely covered with reddish yellow, circular scales. Its leaves are glossy green, egg-shaped NaNsigfig=1NaNsigfig=1 long, NaNsigfig=1NaNsigfig=1 wide and usually scattered in groups of three along the stems. The flowers are arranged singly in upper leaf axils on a very short stalk. There is a leaf-like bract and minute bracteoles at the base of the flower. The five sepals are joined to form a golden-coloured, bell-shaped tube NaNsigfig=1NaNsigfig=1 long, scaly on the outside but glabrous inside. The five petals are joined to form a white tube NaNsigfig=1NaNsigfig=1 long with five lobes on the end. The tube is wider at the top end and the lower, middle lobe is broad elliptic to almost circular, NaNsigfig=1NaNsigfig=1 broad and long while the other four lobes are slightly smaller and roughly similar in size and shape to each other. The petal tube has a few soft hairs on the outside but glabrous inside apart from a densely hairy ring above the ovary and a few hairs on the large petal lobe. Flowering occurs from July to October and is followed by a hairy, oval fruit NaNsigfig=2NaNsigfig=2 long with the sepals attached.[1] [2]
This species was first formally described in 1876 by Ferdinand von Mueller who gave it the name Depremesnilia chrysocalyx and published the description in Fragmenta phytographiae Australiae.[3] [4] In 1931, Charles Gardner changed the name to Pityrodia chrysocalyx.[5] The specific epithet (chrysocalyx) is derived from Ancient Greek words meaning "gold" and "cup", (to give "golden-cupped")[6] referring to the colour of the sepal tube.[7]
This pityrodia grows in sandy loam in open woodland mainly between Esperance, Norseman, Lake Meads and Pyramid Lake in the Coolgardie and Mallee biogeographic regions.[8]
Pityrodia chrysocalyx is classified as "Priority Three" by the Western Australian Government Department of Parks and Wildlife, meaning that it is poorly known and known from only a few locations but is not under imminent threat.[9]