In Victorian England, showing affection in public was just not on, so flowers or rings would be carried or worn to convey covert messages.
Women would often wear flowers or carry small posies of a specific type to indicate that perhaps they were courting and not looking for a husband, or that their love was absent (their sweetheart away at sea was a common theme).
Alternatively they might carry a different flower to indicate that they were single and looking for a husband.
A chap might then give her flowers of a type to tell her he was interested in her. She might then wear a type of flower to indicate that she was interested in him, or a different flower to indicate that she was not.
It was a wonderful system and it meant that a chap would know before he ever asked a girl out if he was in with a chance.
Rings could also be used to indicate the same sort of thing. The one most people in the UK are familiar with is the wearing of engagement and wedding rings on the third finger of the left hand.
Again, a ring on a different finger would be used to encourage suiters, or a different finger to discourage them, and again once approached by a man, whether or not she was interested in him.
Other countries and other cultures wear these rings on a different finger. For example, Prince Albert wore his wedding ring on his little finger (no, not him from Game of Thongs).
My friend from Romania and his wife from Belgium both wear their weddings ring on their right hands.
When my Lovely Cousin gave me a ring as a christmas present, I looked up the correct etiquette in an old book called Enquire Within Upon Everything that had all sorts of advice including the Language of Love. As a result I wore it on the third finger of my right hand as a Friendship Ring.
When we got married, swapping it from my right hand to my left in church was a symbol of the change in our relationship from friendship to friendship and marriage.
A similar system was (and perhaps still is) used in the Gay community by clipping a bunch of keys to different belt loops on their clothes. Left, right, front back etcetera could be used to let others know if they were gay or bi, looking for a partner or already taken.
Again it was a really useful system that saved a lot of embarrassment, and arrests.