Like other citrus fruits, it is native to China. Unlike the common orange, the Myrtle-leaved orange tree has much smaller leaves and very small fruit, about 5 centimeters in diameter. The specific name myrtifolia shows the similarity of its leaves with those of Myrtus communis or myrtle. The Edenic connotations for classical Greco-Roman had the orange trees survive in the medieval Islamic culture, possibly inherited from China itself, where there was widespread tradition that possession of an orange assured happiness to their owners. The Islamic custom of orange trees in trellis-the citrus leaning against the walls as a vegetable display, for ornamental and functional reasons-'to protect them from the cold', as recommended by the Andalusian agronomist Ibn al-Awwam- remains in the transformations made in the Real Alcazar garden by the kings of the house of Austria, in a unique example of continuity of Islamic gardening in the Renaissance of the south of Spain. However, the orange trellis are often of the bitter variety or other citrus, easier to prune than the Myrtle-leaved orange tree, which also reaches high altitude, like the specimens that we can see in the gardens of the Real Alcázar. This development is not only due to the possible age of these trees, but also the tendency to seek more light that characterizes the Myrtle-leaved orange tree.