Commonly known as billy buttons or drumsticks, they are annual or perennial herbs or small shrubs with a cylindrical to spherical head of up to 200 daisy-like "flowers".

The petals are joined to form a small tube and the florets with their surrounding bracts are yellow or golden-yellow.

Plants in the genus Pycnosorus are annual or perennial herbs, with leaves decreasing in size up the stem, those at the base withering first.

[2][3] Plants in the closely related genus Craspedia are also known by the common name "billy buttons" but have their flowers on small stalks rather than attached directly to the receptacle ("sessile") as in Pycnosorus.

[5] The genus was first formally described in 1837 by George Bentham and the description was published in Enumeratio plantarum quas in Novae Hollandiæ ora austro-occidentali ad fluvium Cygnorum et in sinu Regis Georgii collegit Carolus Liber Baro de Hügel .