Try to make your search as simple as possible:
Leptomeria will find all items including that sequence of letters.
Search results for "Leptomeria":
"Leptomeria billardierei" - Leptomeria drupacea
"Leptomeria cunninghamii aff" - Leptomeria empetriformis
"Leptomeria empetriformis aff" - Leptomeria cunninghamii