As a proper noun canna
is .
As a noun plantain is
a plant of the genus
plantago , with a rosette of sessile leaves about 10 cm long with a narrow part instead of a petiole, and with a spike inflorescence with the flower spacing varying widely among the species see also psyllium or
plantain can be a plant in the genus
musa , the genus that includes banana, but with lower sugar content than banana.