In A Pocketful of Rye, Miss Marple is invited to stay at Yew Tree Lodge to help solve some murders. I wondered what a Yew was and investigated- and found that it is a common shrub of which I have multiple specimens in my own garden! We call it Taxus.
Yews are evergreen and produce berries (which are poisonous to people- and therefore it is the means of one of the murders in the story). It was put into the marmalade.