Darling in the Franxx is not a subtle series. Child pilots take on the roles of either a pistil (female pilot) or stamen (male pilot) named after the reproductive parts of a flower. They are paired off and each assigned a FRANXX robot, named after various flowers. Their home is called Mistilteinn, which means “mistletoe.” They are called parasites.
Mistletoe is a hemiparasitic plant that draws nutrients from its host. It is an angiosperm (flowering plant with seeds enclosed in an ovary, as compared with a gymnosperm which has seeds not enclosed in an ovary like a pinecone) that produces berries for means of reproduction. In western tradition, mistletoe is hung during the Christmas holiday and couples that pass underneath it together are expected to kiss. Mistletoes are said to represent romance, fertility, and reproduction.
Again, Darling in the Franxx is not subtle. Heteronormativity is forced — and the series hints that Hiro’s timid personality wasn’t masculine enough for the stamen role — with children put into pairs of the opposite sex in order to pilot robots together. There are too many floral references for this to be a series of coincidences, but it’s up to the series itself to say something about them, otherwise they’ll remain interesting but fairly meaningless trappings.
Hiro and Zero-two pilot the Strelitzia, which is named after the bird of paradise flower. A native plant of South Africa, the bird of paradise flower’s name unsurprisingly comes from the bird of paradise itself since it is brightly-colored like its namesake. It carries a meaning of joyfulness and paradise. This is in contrast to Hiro’s internal monologue of of the jian bird, which he says shares its wings — a direct reference to the fact that he failed out of his piloting program. However, when he pairs with Zero-two, the two seem to be complementary partners. Her hot-blooded nature makes up for his lack of it, and his more demure attitude makes up for her harshness. In other words, Zero-two’s non-conforming pistil — she is called an “ugly sight” and a monster by one of their overseers for devouring her partner — is perfect for Hiro’s untraditional stamen.
All other robots in Darling in the Franxx are named after flowers as well. Delphinium, or larkspur, has a meaning of protection and also ambition of reaching one’s goals. Argentea refers to celosia or plumed coxcomb, meaning affection or silliness. Genista, which calls to mind a “broom” shrub or lupine can hint at creativity and imagination. Lastly, Chlorophytum is a common spider plant, which also carries a meaning of protection.