The current taxonomic revision of this family indicates that on morphological characters, the small genus Sollya is very closely related to the remaining species in Billardiera and perhaps should be sunk into that genus. It is being maintained as a separate genus for now pending the results of molecular analyses to confirm generic level relationships in this family.

Source: Cayzer, L. (2002). Pittosporaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 3. Flowering plants. Dicotyledons. Part 2. The identification of garden and cultivated plants. University of New South Wales Press.