It will be a pineapple. They are often seen also in England carved in stone and set on top for stone gate posts. They were an exotic fruit and only the very wealthy could afford them so they became a sort of status symbol. They started growing them in special hot houses in English stately homes along with other such rarities as apricots, peaches and oranges. Things we take for granted now but would be wildly expensive in the 18th. century. Put the word 'pineapple finial' into the search engine for much more. Thistles are a pain and best dug out with a tool called a 'thistle spud'. Lagopus.....
OK - that makes sense from an on-the-site commentator. Thanks.
