Chinese Date or Indian Plum (Bayar) - The fruit is sour when immature, but very sweet and flavorful when ripe. Botanical name - Zigyphus maurititiana Lamk (source: An introduction to Nepalese Food Plants).
In Southeast Asia, mangosteen is commonly known as the "Queen of Fruit", and is frequently paired with durian, the "King of Fruit". In Chinese food therapy, mangosteen is considered "cooling", making it a good counterbalance to the "heaty" durian.