Which plant has the highest number of species in  Hottonia or Spiraea
Spiraea Spiraea , is a genus of about 80 to 100 species of shrubs in the family Rosaceae. They are native to the temperate Northern Hemisphere, with the greatest diversity in eastern Asia.
Hydriastele Hydriastele is a diverse and widespread genus of flowering plant in the palm family found throughout Australia and New Zealand, Melanesia, Polynesia, and Southeast Asia. It consisted of just nine species until 2004, when molecular research, supported by morphologic similarities, led taxonomists to include the members of the Gulubia, Gronophyllum, and Siphokentia genera. 48 species are now recognized, of which 38 are new combinations, two are new names and one is a new species. It is named in Greek, combining "hydriad", a water nymph in mythology, and "column".