Melicytus novae-zelandiae " subsp. "
 centurionis is a flowering plant in the violet family.
 It is a subspecies of "Melicytus novae-zelandiae", known in New Zealand as Coastal Mahoe.
 The subspecific epithet honours the military Captain James Doran McComish (1881–1948), who made several visits in the 1930s to collect plants on Lord Howe Island.
Coix is a genus of Asian and Australian plants in the grass family.
Melicytus is a genus of flowering plants in the family Violaceae.
 "Hymenanthera" is a synonym.

Question: Are Melicytus and Coix both plants?
Answer: yes