In the past, many European cultures inter- preted forests as a home for the gods and some deities had their own sacred grove or a special tree which was worshiped as a powerful reli- gious symbol. Being the largest of all plants, trees presented a bewildering aspect and must have inspired humans to see them as earthly embodiments of supernatural forces. As in other classical civilizations, ancient Greeks identified certain trees to specific gods but just two groups of trees were elevated to a higher level of con- secration, becoming associated with oracles and predictions: the oak (Quercus sp.) and the laurel (Laurus nobilis L.). Eleven species of Quercus L. (Fagaceae) are native to Greece where they are still used to ornament church yards as in the past they had adorned ancient temples (Baumann, 1993; Strid & Tan, 1997); the genus Laurus L. (Lauraceae) has three species but only one is native to Greece, Laurus nobilis L., the other two— Laurus azorica (Seub.) Franco (Azores), and Laurus novocanariensis Rivas Mart., Lousã, Fern.Prieto, E.Días, J.C.Costa & C.Aguiar— are endemic to Macaronesia (Capelo, 2004; Mabberley, 2008). In Greece, oracles were religious institutions represented by priests and priestesses, where mortals expected to receive wise answers from the gods in response to their questions about state or private affairs. Dispersed throughout the Panhellenic world of city-states, many oracles flourished and vanished but two left records that placed them in a special position among ancient oracles: the Oracle of Zeus at Dodona and the Oracle of Apollo at Delphi. In his book Metamorphoses the Roman poet Ovid (1955) recounted how Daphne, a nymph pursued by Apollo, flew from his advances and was transformed into a laurel tree. From that moment on, laurel became sacred to Apollo, the god of music, poetry, and, above all, prophecies and oracles. The most prestigious oracle was located at Delphi, in mainland Greece. In some Greek traditions, Delphi was literally the centre of the world; the meeting place of the two eagles released by Zeus from opposite ends of Earth. After impaling one another with their beaks, they fell to the ground and the site was marked by the sacred omphalos, or navel stone. Apollo was said to have established himself at Delphi after killing the serpent Python, guardian of the Castalia Spring, and there he provided counsels through the voice of his priestess, the Pythia. Supplicants, carrying laurel branches, approached the Temple of Apollo along a sacred way and, after a preliminary selection, were granted the opportunity to consult the oracle. During her prophetic trance, the Delphic Pythia always held firm a laurel branch in her consecrated hands (Plutarch, 1936) (Fig. 1). At Delphi, laurel branches were used for symbolic reasons only; the prophetic trance of the priestess may have been caused by inhaled ethylene vapors released from the geological faults found near and underneath Apollo’s temple (Hale et al., 2003; Spiller et al., 2008). The oracle issued politically important prophecies, was consulted about democratic reforms in Athens and laws in Sparta, and made pronouncements that led to freeing of slaves and the foundation of new city states (Fontenrose, 1978). Laurel trees were also depicted in the inner sanctuary of Apollo at Didyma (the Didymaion), which had a very active oracle and where one Greek tradition claimed that Leto and Zeus conceived Apollo and his twin sister Artemis. The oak (Quercus sp.) was among the most widely venerated trees, and mythological beliefs associated it with the creation of humans. To the Greeks, oaks were dedicated to Zeus; to the Romans it was Jupiter’s sacred tree, and to the ORACLE TREES In THE AnCIEnT HELLEnIC WORLD Luís Mendonça de CarvaLho, 1, 2 FranCisCa Maria Fernandes, 2 and hugh Bowden 3 We are grateful to Professor Costas Thanos (University of Athens, Greece) 1 Author for correspondence: [email protected] 2 Museu Botânico, Instituto Politécnico de Beja, Rua Pedro Soares, 7800 Beja, Portugal 3 Department of Classics, King’s College London, Strand, London WC2R 2LS, United Kingdom Harvard Papers in Botany, Vol. 16, no. 2, 2011, pp. 425–427. © President and Fellows of Harvard College, 2011.