Tree of Science (Arbre de la ciència, Arbor Scientiae) is one of the most extensive and characteristic works of Ramon Llull, written in Rome between 1295 and 1296. It is a version in encyclopaedia format of General Art or Ars magna aimed to non university public. It has recourse to an analogy common in it: the organic comparison, in which each science is represented by a tree with roots, trunk, branches, leaves and fruits. The roots represent the basic principles of each science; the trunk is the structure; the branches, the genres; the leaves, the species; and the fruits, the individual, his/her acts and his/her finalities. This vegetal allegory shows the influence of Aristotle.