Flower paintings formed a sub-group with its own specialists, and were occasionally the speciality of the few women artists, such as Maria van Oosterwyck and Rachel Ruysch. The Dutch also led the world in botanical and other scientific drawings, prints and book illustrations. Despite the intense realism of individual flowers, paintings were composed from individual studies or even book illustrations, and blooms from very different seasons were routinely included in the same composition, and the same flowers reappear in different works, just as pieces of tableware do. There was also a fundamental unreality in that bouquets of flowers in vases were not in fact at all common in houses at the time – even the very rich displayed flowers one by one in delftware tulip-holders.