The rule I was taught in botany is that the ending should be -ii unless: 1) The person Latinized his name (e.g. Linnaeus or Wislizenus) or 2) The name ends in a vowel or -er (Hence Cuvier ---> cuvieri and Galileo ---> gelileoi). Incidentally, I have seen people name plants after women but use -ii instead of -ae. Joe Laferriere