The remote tropical island of St Helena lies in the South Atlantic Ocean, 1800 km from Africa, a speck of land home to a rich flora and fauna of global importance. Lichens, a fascinating group of specialised fungi which live in close partnership with algae, form a vital part of the island's unique natural heritage. They dominate much of the dramatic, barren lowlands, and extend into the lush, upland cloud forest. This identification guide is the first full treatment since the 19th century, and brings together a wealth of new information based on extensive studies by the author. Covers all 225 known lichens including at least 9 endemics. Over 220 species illustrated in full colour with informative text accessible to beginners, also featuring keys for the professional lichenologist.