The flowers of Nemesia strumosa grow in short, rounded racemes. The calyces are five-lobed, their sepal lobes narrowly oblong.
The two-lipped corolla is five-lobed, the upper lip four-lobed and round-tipped, the lower one one-lobed and bigger, rounded, notched at its tip and pouched at its base. Corolla colours are remarkably varied, ranging from white, cream, yellow, orange, red, pink and mauve. The corolla shape also presents variation in throat markings, the pair of bulges at the lower lip base and hairiness in the throat.
The specific name, strumosa, is a Latin word meaning swelling, referring to the two lower-lip bulges (Manning, 2007; Manning and Goldblatt, 1996; Bond and Goldblatt, 1984; iNaturalist; http://pza.sanbi.org).