Try to make your search as simple as possible:
Sassafras will find all items including that sequence of letters.
Search results for "Sassafras":
"Sassafras officinale" - Sassafras albidum cs
"Sassafras szemu" - Sassafras tzumu
"Sassafras tsumu" - Sassafras tzumu
"Sassafras variifolium" - Sassafras albidum cs