The flowerheads of Vernonia oligocephala grow in wide, flat-topped panicles at the stem tips. The flowerheads comprise only disc florets, lacking the rays around the disc that would complete the classic daisy flowerhead form.
Vernonia flowerheads in general have disc florets in shades of purple. There are about 1000 species worldwide, 50 in South Africa, all in the summer rainfall region. Some vernonias are commonly called ironweed. If the lumpers have it over the splitters in Vernonia taxonomy, there may be rather fewer species compared to the numbers above.
V. oligocephala flowerheads are enveloped by several rows of bracts that are purplish or have purple tips. The disc florets are bright violet, the disc about 1 cm wide (Pooley, 1998; Van Wyk, et al, 1997; www.plantzafrica.com).