The (c. 304 CE) Nanfang caomu zhuang (南方草木狀 Plants of the Southern Regions), attributed to the Western Jin dynasty scholar and botanist Ji Han (嵇含, 263-307), is a Flora describing the plants of Nanyue and Jiaozhi, present-day South China and northern Vietnam. The Nanfang caomu zhuang is the oldest work extant in any language on subtropical botany. The book contains the first descriptions of several economic plants, for instance jasmine and black pepper, as well as the earliest accounts of some agricultural techniques such as biological pest control (using "citrus ants" to protect orange crops), and the cultivation of vegetables on floating gardens (centuries before the earliest recorded Mesoamerican chinampa).