A British marquess is entitled to a coronet bearing four strawberry leaves (three visible) and four silver balls (or pearls) around the rim (two visible). The actual coronet is worn mostly on certain ceremonial occasions, but a marquis can bear his coronet of rank on his coat of arms above the shield.
In the village the working party who had been preparing the decorations for the bridal entry began unpicking the B’s on the bunting and substituting M’s, obliterating the Earl’s points and stencilling balls and strawberry leaves on the painted coronets, in preparation for Lord Marchmain’s return.
Cliffe notes:
These are references to the coronets worn by peers of the United Kingdom on formal state occasions. Earls (such as Bridey) wore coronets which had rims decorated with balls on tall points (or stalks, as they are known), and marquesses (e.g. Lord Marchmain) had coronets with four strawberry leaves alternating with four silver balls. (Dukes’ coronets are distinguished by having only strawberry leaves.) The bunting hung up to celebrate Bridey’s wedding is now being used for Lord Marchmain’s welcome.