Bitter Orange 

The original habitat of the bitter orange (Poncirus trifoliata) is in the Himalayas, China and Japan. The shrub has striking, thorny shoots and fragrant white flowers in May. The fruits are lemon-like berries with a diameter of around 3 to 5 centimetres, which also have an aromatic scent but are inedible when raw. In many parts of the world, the bitter orange is a sought-after grafting base for lemon and orange trees. In the Mediterranean region, the fruits are often made into jam, but are also used as a kitchen spice.