The couriers' speeding horses ruin There was great demand for lychee in the Song Dynasty (960-1279), according to Cai Xiang, in his Li chi pu (Treatise on Lychees). It was also the favourite fruit of Emperor Li Longji (Xuanzong)'s favoured concubine Yang Yuhuan (Yang Guifei). She was also used to eating lychees with the taste of Bashu, so the literati speculated that the lychees that Yang Guifei ate should be tribute from Shu. But lychee is a subtropical fruit. Its evergreen leaves are 12.5 to 20cm (4.9 to 7.9in) long, with leaflets in two to four pairs. Meniu. Lingnan to Changan is more than 2100 kilometers, if there is air transportation, it will be much more convenient.