Streptocarpus pumilus is another dwarf species from just north of Harare in central Zimbabwe to further east near Rusape, closer to the Eastern Highlands of Zimbabwe. It grows in rocks clefts under the protection of often large granite boulders on hills.
S. pumilus is very similar to Streptocarpus cyanandrus in all aspects. The eastern range of Streptocarpus pumilus is about 60 km from the western range of Streptocarpus cyanandrus, a distance often found between different populations of the same species of Streptocarpus. Basically it is a miniature version of Streptocarpus cyanandrus with even smaller leaves (80 x 40 mm) and even smaller flowers (corolla 12-15 mm long). DNA analysis shows that the two species are very close relatives, and their next closest relative is Streptocarpus erubescens which is also very similar. These three species should therefore be examined more closely in future to establish whether they may be one species rather than three.
S. pumilus is one of the very tiny species which hybridizers have tried to use in miniaturizing hybrids. Unfortunately, this hasn’t worked well, and there are only a few cultivars available incorporating the genes of these micro-miniature streps. One of these is S. ‘Blue Streaker’, which involves S. cyanandrus and S. erubescens, species similar to S. pumila.
Part of the problem is cultural, as the tiny species are difficult to grow well, and this characteristic has been passed on to their hybrids.
