Try to make your search as simple as possible:
Nuttallia will find all items including that sequence of letters.
Search results for "Nuttallia":
"Anemone nuttalliana" - Anemone patens b.s.
"Blitum nuttallianum" - Monolepis nuttalliana
"Nuttallia cerasiformis" - Oemleria cerasiformis
"Nuttallia involucrata" - Callirhoe involucrata
"Poa nuttalliana" - Puccinellia nuttalliana