About Elephant Ears
Billy Bates, New Albany, MS, USA, asked our email discussion list:
Can anyone explain the difference in Alocasia, Colocasia and Xanthosoma?
Horace Hobbs, Houston, TX, USA, replied:
According to the recent Kew publication "The Genera of Aracea", Colocasia and Alocasia are genera in the Tribe Colocasieae of the Family Araceae with no particular botanical Alliance within the family. Xanthosoma is a genus in the Caladium Alliance in the Tribe Caladieae, Family Araceae.
For Colocasia and Alocasia -- the botanical difference is based on the number and placement of ovules (female goodies) on the inflorescence (bloom thingie) and the only foliar distinction is that sometimes Alocasia leaves are sometimes pinnatifid (sort of fernlike, or like Stangeria in Cycadacea, or arrow shaped)
Xanthosoma blooms are quite different from Colocasia or Alocasia especially with respect to the female parts and Xanthosoma also produces sterile flowers between the male and female ones.
Horticulturally, they are all in the same boat with wide variation of requirements. Some do well in very wet positions and others do not. I have several species of each genus and am randomly experimenting with them in the pond -- so far, all seem prefer to be out of the pond with lots of fertilizer and every day watering.
Reference: S.J. Mayo, J. Bogner, and P.C. Boyce. The Genera of Aracea. The Royal Botanic Gardens, Kew, 1997.