LOL. This is a perennial subject. You know, Latin was a written language spoken only by Lawyers. SO the rules of pronumciation are largely synthetic and matters of convention.
Leucophylla can be pronounced many ways, and is. No one can say which is correct. I pronounce it as Lew-coe-fie-la, with the accent on the "fie".
I have heard others pronounce it Lew-coff-ill-a with the accent on the "coff". Our friends in the UK would probably find this correct.
I think the long "I" sound is correct. We refer to Class, Order and Phyllum (pronounced Fie-Lum).
SO the "Y" takes a long "I" vowel sound, as in "cycle". We don't pronounce this as sickle (although many do pronounce bicycle as bi-sickle, incorrectly)
Terminal sounds like -ae are pronounced as ay-EE (with the same sound as in "eight" only with the long "E" termination.
-ce/-ci seems to take the soft see sound as in census, central, circut, centenial (so properly Sahr (or sair)-uh-SEN-ee-uh)
-iensis: ee-en-sis (as in madagascariensis)
ia: ee-uh
Hope this helps. Remember, there is no real right way, and be kind in correcting others pronunciation.
(elarwhis and nepG have the hang of it I think!)