A Midsummer Night's Dream

 The line is:

"I know a bank where the wild thyme blows,

Where oxlips and the nodding violet grows,

Quite over-canopied with luscious woodbine,

With sweet musk-roses and with eglantine..."

30 years later, in the middle of the night, it occurs to me that I might have said "Quite o'er-canopied" rather than "over-canopied...'

And now I can't sleep!