"'A vucchella" is a Neapolitan song composed by Paolo Tosti.
With the Neapolitan melodic song tradition being so popular worldwide, D'Annunzio wanted to prove himself able to write in the Neapolitan dialect, and managed to do so quite convincingly for this song, "La vucchella".
[1] One interpretation is that the woman's mouth is like a little rose's petal when it becomes a bit dried out and battered in the cold weather.
[1] D'Annunzio was known as a lover of women of all ages, so one cannot exclude the possibility that the woman in question, whose rose-like dried mouth the poet was writing about, was in her late forties or even older.
[3] The text does not belong to the old Seventeenth/Eighteenth century Neapolitan lyric tradition, and was specially written for Tosti by Gabriele D'Annunzio in the first half of the 1900s.