The flowers of Jamesbrittenia aurantiaca are borne solitary from leaf axils on long, erect pedicels. A green, lobed calyx clutches the back end of the corolla. The five petals form a cup-shaped throat, yellow inside with distinct parallel dark lines from the centre. Outside the corolla cup the pale orange petals spread with margins rounded.
The ovate black fruit suspended in a persistent, short, green calyx appears glossy (Pooley, 1998; Van Wyk and Malan, 1997; iNaturalist).