Try to make your search as simple as possible:
Mussaenda will find all items including that sequence of letters.
Search results for "Mussaenda":
"Mussaenda formosa" - Randia formosa
"Mussaenda nitida" - Randia nitida
"Mussaenda spinosa" - Randia armata
"Randia mussaenda" - Randia formosa