Gordon Douglas Rowley (1921-2019) was born in London. He taught horticultural botany at Reading University. He had served as editor of various botanical publications, and had written over 300 articles. Rowley has several plants named for him including the very popular Senecio rowleyanus or String of Pearls, Lobivia rowleyi, Pygmaeocereus rowleyanus, and Echinopsis rowleyi.
In 2013, Rowley published “Generic Concepts in the Alooideae” (Part 3 and 4) in Alsterworthia International. Based on the earlier genetic studies from Barnabas H. Daru et al, he gave rise to the 3 Haworthia subgenera from Bayer to separate genera: subg. Haworthia → Haworthia, subg. Hexangulares → Haworthiopsis, and subg. Robustipedunculatae → Tulista. However, Rowley adopted a very broad concept of Tulista, which also includes Astroloba, Aristaloe, and Gonialoe. This was later rejected by Manning et al.