The classification of the three subgenera within the genus Haworthia is based on the floral structure. In the subgenus Robustipedunculares the flowers have a straight tube and are broad at the base.  These flowers adorn a multi branched flower stalk and open one at a time, typically each staying open for only a day or two.  The fruits grow to be round and pea sized, quite different than the other two Haworthia subgenera.  This subgenus consists of only four species, minima, marginata, kingiana and pumila.  The last three grow to be quite large, and pumila is the largest Haworthia.  These plants superfically resemble Haworthia attenuata with white turbercles (although marginata (and some times the others) is generally glaberous.