The Buddha's hand citron (Citrus chirocarpus) derives its Chinese name fo shou and the alternative English one of "finger citron" from its odd shape. It symbolises "much happiness" and is used as an offering for the altar during Chinese New Year. It's rind is highly aromatic and believed to be demon-repelling making it highly prized. The dried peel is also thought to possess remarkable medical qualities.
When in decorative art combined with a bat, fu, which is a pun symbol for 'happiness', the combination becomes a rebus for "more and more happiness" (Fu Shang Jia Fu).