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 (South Africa). He was honored on for his work on the genus Haworthia when a plant generally known as H. “uniondalensis”, was published as H. bayeri.
Bayer’s time at the Karoo Garden allowed him to work extensively on Haworthias, many of which were from Smith‘s collection. Bayer authored the first book Haworthia Handbook in 1973. He recognized and extended Uitewaals’ division of the genus based on floral characteristics, creating 3 subgenera: Haworthia, Hexangulares, and Robustipedunculatae. His work on Haworthia continued, and had since published The new Haworthia handbook (1982), Haworthia revisited (1999) and Haworthia update Vol. 1-8 (2002-2012). Bayer reduced the number of Haworthia species dramatically, and most of his classifications are still used to this day.