Streptocarpus longiflorus was previously described as Streptocarpus caeruleus ssp. longiflorus to separate it from its closest relative, Streptocarpus caeruleus ssp. caeruleus. Streptocarpus longiflorus occurs on the Blouberg, an isolated mountain to the west of the Zoutpansberg.  Streptocarpus longiflorus grows on the wetter habitats in shaded areas under trees or secluded gullies on the Blouberg whilst Streptocarpus caeruleus grows on drier more exposed habitats there and in the western Zoutpansberg.

Streptocarpus longiflorus has oblong leaves (reaching 300 mm long x 70 mm wide) on a rosulate plant consisting of 5 – 10 leaves, inflorescences 5 – 15 flowered, corolla 38-47 mm long, funnel shaped with rounded lobes 8-10 x 10-12mm, the lower lip is 15-18 mm long. The flowers are a deep sky blue/purple with a y-shaped yellow bar on the floor of the corolla which varies in thickness and splits towards the corolla opening. The flowers are very attractive but the species has not been used for hybridization due to its inaccessibility but it has distinct potential for horticulturists and hybridizers.