The old, brown flowerhead of Cullumia aculeata in picture still retains its long spines on the margins and tips of the involucral bracts. There are stem-leaves right up to the flowerhead. The photo was taken during April.
When flowering, the involucral bracts form a cup-shape below the yellow flowerhead. The receptacle at the base of the head is honeycombed, without scales.
Spreading to a diameter in excess of 2 cm over the involucre is a whorl of sterile, yellow ray florets, maroon on their outer surfaces. They encircle a small disc packed with tiny yellow florets that are fertile and deeply five-lobed. Flowering happens throughout the year.
The fruits have no pappuses in Cullumia, differentiating them from Berkheya (Vlok and Schutte-Vlok, 2015; Moriarty, 1997; Bond and Goldblatt, 1984; iNaturalist; www.worldfloraonline.org).