Location continental Africa: This section contains some species which were previously placed in monotypic genera such as Acanthonema and Trachystigma. Both these former genera have very short capsule lengths which do not allow them to twist because of which they were excluded from Streptocarpus before. The species now described as Streptocarpus manni was originally described as Trachystigma manni (Clarke, 1883) and Streptocarpus strigosus was originally described as Acanthonema strigosum by Hooker J.D. (1862). The species originally described as Carollofritschia diandra by Engler (1899) was subsequently named Acanthonema diandra by Burtt (1981) after which it was then renamed Streptocarpus diandrum by Nishii et al., 2015. The species in these three former genera are now placed in the same Section in the new taxonomy. The section has been given the name Trachystigma to uphold the one genus name of the previous taxonomy.
Other than the seed capsule description, the species in this section are fairly typical for Streptocarpus, there are unifoliates and caulescent species in the same genus which appear unusual, but DNA analysis groups them together. Their geographical distribution in western Africa does support the fact that they are placed in a single group. Streptocarpus nobilis which has a deep purple corolla color is certainly attractive horticulturally, but other than that the species in this section are unlikely to be of particular horticultural interest.
Species in section Trachystigma:
Streptocarpus diandrum
Streptocarpus insularis
Streptocarpus mannii
Streptocarpus nobilis
Streptocarpus strigosus