PURPLE PASSAGE, also purple patch, purple prose. A piece of writing marked by a florid, fanciful style:
There are few of us who have not sometimes wakened before dawn, either after one of those dreamless nights that make us almost enamoured of death, or one of those nights of horror and misshapen joy, when through the chambers of the brain sweep phantoms more terrible than reality itself, and instinct with that vivid life that lurks in all grotesques, and that lends to Gothic art its enduring vitality, this art being, one might fancy, especially the art of those whose minds have been troubled with the malady of reverie.(from Oscar Wilde , The Picture of Dorian Gray, 1890, ch. 11)
See POETIC DICTION.

pur·ple pas·sage • n. an elaborate or excessively ornate passage in a literary composition.