The classification of species within Brassicaceae is gradually resolving through molecular phylogeny investigation, using internal transcribed spacer (ITS) data and other new-found sequencing knowledge.
[3][4] Previously there were six genera within the tribe Heliophileae, all endemic to southern Africa: Heliophila, Cycloptychis, Schlechteri, Silicularia, Thlaspeocarpa, and Brachycarpaea.
Following extensive analysis of molecular evidence (nuclear (ITS) and plastid (trnL-F) DNA sequence data), Heliophileae was found to be monophyletic and the five small genera were reduced to synonymy with Heliophila.
The majority of the species grow in the winter-rainfall Cape Floristic Region and the more arid Namaqualand, while a smaller portion extend to the rest of South Africa, Namibia, Eswatini, and Lesotho.
Flower size, for example, varies greatly, with this genus containing both the largest of petals within the family (H. juncea) to the smallest (H. pectinata).