Allen J. Coombes - The Book of Leaves: A Leaf-by-Leaf Guide to Six Hundred of the World’s Great Trees

The University of Chicago Press, Chicago 60637

The University of Chicago Press, Ltd., London

The Ivy Press Limited 2010

All rights reserved. Published 2010

ISBN-13: 978-0-226-13973-9 (cloth)

ISBN-10: 0-226-13973-5 (cloth)

eBook ISBN: 978-0-226-17686-4

Library of Congress Cataloging-in-Publication Data

Coombes, Allen J.

The book of leaves : a leaf-by-leaf guide to six hundred of the worlds great trees / Allen J. Coombes ; edited by Zsolt Debreczy.

p. cm.

Includes bibliographical references and index.

ISBN-13: 978-0-226-13973-9 (cloth : alk. paper)

ISBN-10: 0-226-13973-5 (cloth : alk. paper) 1. TreesIdentification. 2. LeavesPictorial works. I. Debreczy, Zsolt. II. Title.

QK477.2.I4C66 2011 581.48dc22

2010009779

The paper used in this publication meets the minimum requirements of the American National Standard for Information SciencesPermanence of Paper for Printed Library Materials, ANSI Z39.48-1992.

Color origination by Ivy Press Reprographics.

This book was conceived, designed, and produced by

Ivy Press

210 High Street, Lewes East Sussex BN7 2NS United Kingdom www.ivy-group.co.uk

Creative Director PETER BRIDGEWATER

Publisher JASON HOOK

Art Director MICHAEL WHITEHEAD

Editorial Director CAROLINE EARLE

Senior Editor LORRAINE TURNER

Assistant Editor JAMIE PUMFREY

Consultant Reader DR. PETER GASSON

Design and Map Artwork GINNY ZEAL

Photography ISTVN RCZ & ZSOLT DEBRECZY

Illustrators ADAM HOOK, CORAL MULA

Picture Research KIM DAVIES

ALLEN J. COOMBES is coordinator of scientific collections at the Herbarium and Botanic Garden of the University of Puebla, Mexico. He was previously botanist at the Sir Harold Hillier Gardens in Hampshire, England. He is the author of several books on trees and plants and was president of the International Oak Society from 2006 to 2009.

ZSOLT DEBRECZY is research director of the International Dendrological Research Institute, Inc., Boston, Massachusetts, USA. He holds a PhD in botany and began his career as curator of the Bryological Collection in the Botanical Department of the Natural History Museum, Budapest, Hungary. He is the author of several books focusing on temperate-zone woody flora and vegetation.

THE BOOK OF LEAVES

A LEAF-BY-LEAF GUIDE TO SIX HUNDRED
OF THE WORLDS GREAT TREES

ALLEN J. COOMBES

EDITED BY ZSOLT DEBRECZY

THE UNIVERSITY OF CHICAGO PRESS
Chicago and London

CONTENTS

Leaves are a true miracle of nature. They perform a job that science still only dreams of fully understanding: they transform dissolved minerals and other elements into the organic matter that eventually forms the shoots, leaves, roots, flowers, and fruits that create the Earths rich layer of humus and soil, and build its wondrous forests and habitats. Leaves, or specifically the chlorenchyma cells within the mesophyll, make possible the material connection between the Suns energy and life on Earth.

Evergreen leaves can provide significant year-round interest. This Cherry Laurel (Prunus laurocerasus), which is commonly grown for its attractive foliage as well as for providing shelter, is a classic example.

Morphologically, leaves are modified, flattened shoot-systems. Many scientists in the field of evolutionary morphology believe that over geological time, plants lateral outgrowths gave rise not only to leaves but also to reproductive organs such as petals, sepals, carpels, and stamens.

Leaf shape varies hugely, both within and between species. Yet the basic character of a leaf is usually typical enough to help with species identification. So, The Book of Leaves is about tree identification as well as about leaves. Other identifiers, such as flowers and fruits, are ephemeral, but the leaves remain throughout a trees growing season. A leaf can be simple; that is, with a single blade adjoining the stem; or distinctly compound, with few or many leaf-parts (leaflets). A leaf can be entire, shallowly to deeply lobed, or cut toward the central vein. Characters of the leafs surface provide additional identifiers, such as whether or not the leaf is hairy, and whether the hairiness is sparse or dense, rough, or soft.

The leaf selection introduced here is limited to the temperate zone, that Era (starting about 65 million years ago) to the present. This flora first appeared in the northern part of a much warmer Earth (an average temperature of 72F/22 C compared to 57 F/14 C today). It gradually evolved to resist physiological coldprimarily by being deciduous in winter or, if evergreen, by other morphological and physiological strategies. This ability saved most or many species as the planet gradually cooled, reaching its low-temperature minimums in periods starting some half-million years ago.

As for leaves from the southern hemisphere, in this book they are represented by a somewhat more moderately cold-resistant flora that survived and evolved in South America and New Zealand and in the southernmost part of Australia, particularly the wet conditions of Tasmania and the mountains of southern Australia. The Book of Leaves thus covers a large segment of the trees that can be observed in forests, or in arboreta, throughout the temperate world.

Documenting trees and photographing leaves is a true pleasure for any nature lover. Leaves are intrinsically beautiful, and can inspire deep feelings. Go for a walk in an arboretum, and you might notice how similar the related temperate-zone species can be, even though one may be from North America and the other from southern Asia. This is because they are indeed closely related; climatic differences and millions of years of divergent geological history have merely blurred their similarities. This book you now hold is, one might say, a kind of paper arboretum, a place where trees and leaves that the eons have dispersed have been successfully and satisfactorily reunited.

Zsolt Debreczy

The European Wild Pear (Pyrus pyraster) is one of a few species in its genus to have small, rounded leaves.

Nature will bear the closest inspection. She invites us to lay our eye level with her smallest leaf, and take an insect view of its plain.

HENRY THOREAU , 1839

In spite of their importance to life, their abundance, and their presence over a large proportion of the year, leaves are perhaps the least appreciated part of a tree. We often talk of beautiful flowers or wonderful bark, but leaves are generally accorded a mention only for their brief, but often spectacular, fall color. As L. Frank Baum wrote in The Land of Oz For the common folks are like leaves on a tree, and live and die unnoticed.

The Hubei Crab Apple (Malus hupehensis) has an ovate form. Whatever their shape, all leaves are adapted to perform a range of complicated functions.