A developmental process, independent of morphogenetic (shape) change, that is required for the facial nerve to attain its fully functional state. This sensory and motor nerve supplies the muscles of facial expression and the expression and taste at the anterior two-thirds of the tongue. The principal branches are the superficial ophthalmic, buccal, palatine and hyomandibular. The main trunk synapses within pterygopalatine ganglion in the parotid gland and this ganglion then gives of nerve branches which supply the lacrimal gland and the mucous secreting glands of the nasal and oral cavities. [ https://www.worldcat.org/search?q=bn%3A0838580343 GOC:cls GOC:dgh GOC:jid http://purl.obolibrary.org/obo/go/references/0000021 GOC:dph ]