Streptocarpus caeruleus was previously described as Streptocarpus caeruleus ssp. caeruleus to separate it from its closest relative, Streptocarpus caeruleus ssp. longitubus now Streptocarpus longitubus. Streptocarpus caeruleus occurs on the Zoutpansberg Mountain range in far northern South Africa, in various forms and also on the Blouberg, an isolated mountain to the west of the Zoutpansberg where it grows close to Streptocarpus longitubus. Streptocarpus caeruleus grows in drier habitats on the Blouberg and the western Zoutpansberg in rock cracks in unforested rocky outcrops. Still on the Zoutpansberg, but to the east it grows in the densely forested Hanglip Reserve just north of the town of Louis Trichardt.
Streptocarpus caeruleus has typically obovate leaves on a rosulate plant (80-150 mm long and 30- 80 mm wide), but its flower dimensions vary considerably depending on where it comes from. In the forested Hanglip Reserve, the flower is much smaller with reduced corolla lobes. It shares the habitat there with Streptocarpus parviflorus ssp. soutpansbergensis with which it also hybridizes. In the west of the Zoutpansberg Range, the corolla is almost double the size and on the Blouberg it is again smaller. All forms are characterised by flowers that often approach sky blue, with some degree of purple overtones, and two yellow markings on the corolla floor. The flowers are very attractive. The species has not been used in hybridization but its flowers show that it certainly has future potential for horticulturists.
