Botany is handled in Books XII to XVIII, with Theophrastus as one of Pliny's sources. The manufacture of papyrus and the various grades of papyrus available to Romans are described. Different types of trees and the properties of their wood are explained in Books XII to XIII. The vine, viticulture and varieties of grape are discussed in Book XIV, while Book XV covers the olive tree in detail, followed by other trees including the apple and pear, fig, cherry, myrtle and laurel, among others.