Sentence:  Though wit may flash from fluent lips, and mirth distract the breast, / Through midnight hours that yield no more their former hope of rest; / 'Tis but as ivy-leaves around the ruined turret <WSD>wreath</WSD> / All green and wildly fresh without, but worn and grey beneath. 
Meaning of the word marked with <WSD> tags:  To curl, writhe or spiral in the form of a wreath.