Nemesia bicornis flowers grow in panicles or branched racemes, the plants often many-flowered.
The two-lipped corollas have four oblong, round-tipped lobes in the upper lip, one large and wavy lobe in the lower one with four velvety, often yellow swellings on the base of this somewhat hairy lower lobe. Flower colour is white to lilac with about parallel grey or red-brown veins low on the upper lip. The flower is about 4 cm long. There is a 4 mm spur with slightly swollen tip at the back of the corolla.
Flowering happens from before midwinter to early spring.
The fruits are triangular or broadly two-horned capsules, giving the species its specific name: bicornis is derived from the Latin word bis meaning twice and cornu meaning a horn (Vlok and Schutte-Vlok, 2015; Manning, 2007; Le Roux, et al, 2005; iNaturalist).