Martin Bruce Bayer (1935-) was born in Empangeni, South Africa. He worked as a curator of the Karoo Botanical Garden in Worcester and later a research ecologist with the Dept. of Agriculture. H. bayeri, formerly known as H. ‘uniondalensis’, was after for him.
Bayer’s time at the Karoo Garden allowed him to work extensively on Haworthias, many of which were from Smith‘s collection. He published the first book Haworthia Handbook in 1973. He recognized and extended Uitewaal‘s division of the genus based on floral characteristics, creating 3 subgenera: Haworthia, Hexangulares, and Robustipedunculatae. Bayer had since published The New Haworthia handbook (1982), Haworthia revisited (1999) and Haworthia Update. Vol. 1-8 (2002-2012). He reduced the number of Haworthia species dramatically, and most of his species are still recognized to this day.