1973, a lotus pollen fossil was found in Hemudu cultural site 7,000 years ago in Yuyao County, Zhejiang Province, and two carbonized lotus seeds were found in Yangshao cultural site 5,000 years ago in the same year. Professor Ren Xu, a paleobotanist, discovered the lotus leaf fossil100000 years ago in Qaidam basin. Lotus likes water, temperature and light, and has strict requirements on temperature. Germination began at 8 ~ 10℃, underground stems sprouted at 14℃, and "money leaves" grew at the same time. It begins to shoot and grow leaves at 18 ~ 2 1℃, which is not conducive to bud development and development at 23 ~ 30℃. The growing season needs plenty of sunshine.