In our modern world, the spiny-stemmed flowers, intertwined leaves, and delicate pink blossoms of the rubus fruticosus, or common blackberry bramble, might catch the eye of the casual observer or weekend gardener. Pleasant, prolific, and decorative, plants like the blackberry are looked upon as sources for harvest, landscape, and visual pleasure. To the medieval and Renaissance artist, however, these botanicals were far more. Part of a richly...