This is the place to post questions and discussions on usage and style. The members of the Wordwizard Clubhouse will also often be able to help you to formulate that difficult letter.
I would call it a [floral] bonnet.
I agree with Erik.
P.S. As I understand it, the main purpose of the design of a bonnet is to protect a lady's hairdo, whilst travelling, from the wind and the rain so that she can arrive at the gathering with coiffure intact.
I'm puzzled therefore I think.
Erik and tony h : Thank you two so so much. I really appreciate it.
End of topic.