Advances in BOTANICAL RESEARCH VOLUME 17 Advances in BOTANICAL RESEARCH Editor-in-Chief J . A. CALLOW School of Biologicul Sciences, University of Birminghum, Birminghum, England Editorial Board John Innes Institute, Nor 1 3 ich , England Depurlrnent of Botany, Royal Hollowuy & Bedford N i w College, University of London, Egh um Hill, Eghum , Su r rey , Engliin cl E. A. C. MAcROBBTE Depurtment Qf Botany, Universit,v of Ccimhr idge, Cumhridge, Englund H . W. WOOLHOUSE W. G. CHALONER Advances in BOTANICAL RESEARCH Edited hi, J. A. CALLOW VOLUME 17 1990 ACADEMIC PRESS Harcourt Brace Jmanovich, Publishers London San Diego New York Boston Sydney Tokyo Toronto This book is printed on acid-free paper ACADEMIC PRESS LIMITED 24/28 Oval Road, London NWI 7DX United Stales Edition published by ACADEMIC PRESS INC. San Diego, CA 92 I0 I Copyright i t ' 1990 by ACADEMIC PRESS LIMITED All rights reserved No part ol' this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy. recording. or any information storage and retrieval system. without permission in writing from the publisher. British Library Cataloguing in Publication Data Advances in botanical research.-Vol. 17 I . Botany-Periodicals 581'.05 QKI ISBN 0-1 2 -00591 7-7 Typeset by Eta Services (Typesetters) Ltd, Beccles, Suffolk Printed by Galliards (Printers) Lld, Great Yarmouth, Norfolk CONTRIBUTORS TO VOLUME 17 M. E. COLLINSON, Dicisioti of' Biosphere Sciences, King's College Lonllon, Kcwington Cutitpus, Cutitp(lc.ti Hill RoLid, London Wbr 7A H , U K P. K . EN DRESS, Dt~purtt?i~tit of' S j ~ s ~ t w t i ~Botutij-, tii~ Univc~rsitj~ of' Zurich. Zuricli, S\j.itxrlund E. M . FRIIS, Department of' Palueohotany, Swedish Museum of Natural His t o r j ., SIock /I olm , S1t w l e t i I. M . MILLER. Depurttiimr of' Biologkul S c i m ~ t ~Wright s, Statc Uniwr.sitj*, Duj-ton. O H 45435, USA J. F. V. VINCENT, Biomechanics Group, Departments of Zoology and Engiricrring. LJtiiversitj~of Rwtliti~g.Wliitekniglits, PO Bos 228, Reuiling, UK This Page Intentionally Left Blank PREFACE In this volume of Adiwncv.v it1 Botriniul Rc.vwrc~lrwe start with two reviews on aspects of primitive floras and angiosperm evolution. Collinson's article is concerned with the Early Tertiary or Palaeogene era, a time of major geological and evolutionary change producing new microhabitats and competitive pressures. The resultant radiations of flora and fauna (including the second radiation of angiosperms) represent the early stages in the evolution of the communities and biological diversity that characterize the modern world. Collinson's review is concerned with the study of the floras of this period a s they aid in the deduction of ancient climate and ecology. A more complete understanding of the latter is not irrelevant to current predictions of global climatic change! The review examines the geological and biological contexts of the period before embarking on a reconstruction of climate a s inferred from physiological indicators such as carbon isotope ratios. from comparative anatomy and the study of fossil communities and plant-animal associations. Moving to a slightly earlier geological period, during the last few years there has been a number of spectacular discoveries of well-preserved Early and mid-Cretaceous flowers. Study of floral development and biology of living archaic angiosperms has also intensified. In their chapter. Friis and Endress argue that the time is ripe for the two areas of study to come together, to encourage a synthesis of these sources of information into a new theory of how flowers evolved. This extensive review prov