Worn as a pair at an angle the convulvus (bindweed) flowers are a perfect translation of the field flower into a lively jewel. They stand out by their naturalistic and balanced design as well as their supreme workmanship. In fact, they are of some interest in the history of jewellery as they display an early use of the famed calibré-setting, where the stones are set in such a way that no prongs or supporting metal may be seen. This type of setting was patented in the mid-1930s and Boivin's use of the technique already in 1937 shows that not only were they ahead of their time in terms of design but were also at the forefront of technical developments. This pair of flower brooches rank amongst the greatest floral master pieces ever produced by Boivin or indeed by any other jeweller in the 20th century.