Why is Louisa Collins known as the Borgia of Botany?

I've received so many emails in response to the story in Good Weekend (19/10) and one question that has arisen is: why was Louisa called the Borgia of Botany?

Two reasons: first, because Louisa supposedly used poison to dispatch her husbands (once you've read the book, you'll be able to decide for yourself whether she was guilty.)

The name Louisa sounds a little like Lucrezia - and Lucrezia Borgia is a famous figure in Renaissance history: the daughter of a Pope, she is rumoured to have owned a hollow ring, which she would fill with poison to drop into the drinks of her family's enemies.

Second: because Louisa lived in Botany, of course!