Here is a nice example of decoration that is useful. When you ink and print from a small area of type for a specimen, it’s good to have some support for the rollers and the paper. This way you avoid over-inking at the edges of the type area. So in this 1637 specimen of Brevier Hebrew, bought by Samuel Brown from the estate of Arend Cornelisz. van Hoogenacker in Leyden for Oxford University, a border of printer’s flower is literally in a supporting role. (Brown was swindled – few of the founts were complete – and putting them in order was a major task.)
Barker, The Oxford University Press and the spread of learning (1978), p. 11