Try to make your search as simple as possible:
Glaucium will find all items including that sequence of letters.
Search results for "Glaucium":
"Glaucium flavum v. aurantiacum" - Glaucium flavum fa. fulvum
"Glaucium leiocarpum" - Glaucium oxylobum
"Glaucium leptopodum" - Dicranostigma leptopodum