ἐστεφάνωσε: The middle (O. 7.15), though natural, is not necessary. χαίταν represents ἓ αὐτόν. So P. 10.40: κόμας ἀναδήσαντες.
πτεροῖσι: Cf. P. 9.135: πολλὰ δὲ πρόσθεν πτερὰ δέξατο Νίκας. Wreaths are wings, because they bear the champion aloft, ἐπαείροντι (O. 9.23).