The leaves of Berkheya onobromoides become 20 cm long and 50 mm wide, not including the spines. It is easy to see why many Berkheya species are named dissel (thistle) in Afrikaans, looking at all the long, threatening spines on plants in this Album.
The bright to pale green leaves of B. onobromoides are straight and narrow, folding in along their whitish midribs. There are conspicuous, deep lateral lobes appearing irregularly along the leaf margins that are markedly spine-toothed. The leaf tapers slowly to its base. Basal leaves are the longest (Bond and Goldblatt, 1984; iSpot; Vlok and Schutte-Vlok, 2010).