The unscented, yellow flowers of Gnidia simplex grow in small stem tip clusters. They are hairless, apart from the receptacle at the base. The tips of the involucral leaves reach about as high as the corolla which they surround.
The corolla tube is hairless and funnel-shaped, resembling that of G. juniperifolia that has slightly broader leaves and broader involucral leaves. There are four membranous, petal-like scales at the flower mouth, alternating with the four petal lobes and about half their size. The petal lobes taper to acute tips that may recurve slightly.
The taller of the two whorls of stamens protrudes slightly above the flower mouth, the style a bit shorter. The stigma of the flower in picture has hair-like branches. Flowering occurs from late spring to mid-autumn (Manning, 2007; JSTOR).