Costmary (Tanacetum balsamita), also called alecost or "Bible leaf," is a tall daisy-family perennial whose long, silvery grey-green leaves give off a warm, balsamic scent that lands somewhere between spearmint and lemon-balm with a resinous, faintly bitter edge. A cottage-garden herb of the medieval and Tudor still-room, it was steeped into ale before hops (hence "alecost"), tucked as a fragrant page-marker into prayer books and Bibles, and rubbed sparingly into salads, stuffings and sweet dishes.