Try to make your search as simple as possible:
Royena will find all items including that sequence of letters.
Search results for "Royena":
"Royena hirsuta" - Diospyros hirsuta
"Royena lucida" - Diospyros whyteana
"Royena pallens" - Diospyros pallens
"Royena whyteana" - Diospyros whyteana