"there were gilly flowers growing below the windows which on summer evenings filled them with fragrance"
Creative Commons AttributionWallflowers - Credit: Rhian, Flickr
A variety of Sweet William
GNU Free Documentation LicenseA variety of Sweet William - Credit: 'Jonathan Zander (Digon 3)', Wikimedia Commons

Gilly flower, or gillyflower, is the name given to a large number of different fragrant flowers, including carnations, pinks, stocks, sweet Williams and wallflowers.

The clove pink (Dianthus caryophyllus), for example, is known as the clove gillyflower.