Dissertatio Botanica de Dracæna [Dragon trees]

Dragon trees are a genus of about 120 species of trees and shrubs in the family Asparagaceae, native almost exclusively to Africa. Some of the smaller species are popular as houseplants and have earned a “green” reputation for their ability to clear pollutants from the air. They are the focus of this university dissertation written by Professor Carl Peter Thunberg. In 18th- and 19th-century Europe, professors wrote the dissertations; the student’s job was to explicate and defend it and pay for its publication. SIL holds dozens of these botanical and zoological papers by the great systematist Carl von Linné (Linnaeus) at the University of Uppsala and his student and successor Thunberg.