EVOLUTIONARY STUDY ON THE TERTIARY FAGACEAE

壳斗科是乔木和灌木的一个大科，分布在南北半球。本项目的目的是在宏观和微观化石的基础上，研究该科各属的系统发育和地层分布。从日本154个地区收集了近200个现存的油麻叶片，对叶片的结构特征进行了研究。研究表明，在不同的气候条件下，脉状分布，尤其是细脉数和小孔大小是不变的。重新研究了东亚地区已知的fagus属植物的叶脉和种子形态，并将其重新命名为8种。将这8种植物与世界上现存种进行比较，表明东亚的铁扇属植物起源于大叶组，在中新世中期分化为2个门，日本现存的2种植物出现于中新世晚期。通过对220种栎树叶片的研究，建立了栎属亚属和剖面的叶片结构鉴定体系。在此基础上，东亚第三纪橡树叶化石被重新划分为12种。始新世至中新世早期的落叶栎树均属于cerris和alae剖面，而ilex、亚亚和齿科的落叶栎树则出现在中新世中期以后。然而，青冈叶化石在系统发育方面仍未得到解决。对世界上报道的壳斗科化石进行了研究。壳斗科3个亚科的分化发生在古新世或始新世早期，与现存属毫无关系的标本是在始新世晚期或渐新世早期首次确认的。

THE FAGACEAE IS A LARGE FAMILY OF TREES AND SHRUBS, WHICH ARE DISTRIBUTED IN THE BOTH HEMISPHERES. IT IS THE PURPOSE OF THIS PROJECT TO INVESTIGATE PHYLOGENY AND STRATIGRAPHIC DISTRIBUTION OF EACH GENERA OF THIS FAMILY, BASED ON MACRO-AND MICROFOSSILS.1. NEARLY 200 LEAVES OF THE EXTANT FAGUS CRENATA COLLECTED FROM 154 LOCALITIES OF JAPAN, WERE EXAMINED ON LEAF ARCHITECTURAL CHARACTERS. THIS INVESTIGATION SHOWS THAT THE VENATION, ESPECIALLY VEINLETS NUMBER AND AREOLE SIZE, IS INVARIABLE AGAINST THE DIFFERENT CLIMATIC CONDITIONS OF SAMPLING LOCALITIES.2. REINVESTIGATING THE VENATION DETAILS FOR FOSSIL LEAF AND MORPHOLOGY FOR FOSSIL CUPULES AND SEEDS, ALL THE KNOWN SPECIES OF THE GENUS FAGUS IN EAST ASIA ARE REDESIGNTED AS 8 SPECIES. THE COMPARISON OF THESE 8 SPECIES WITH THE EXTANT SPECIES OF THE WORLD, REVEALS THAT EAST ASIAN FAGUS ORGINATED FROM THE F. GRANDIFOLIA GROUP, DIVERGED TO TWO PHYLADS IN THE MIDDLE MIOCENE, AND THAT THE TWO EXTANT SPECIES OF JAPAN APPEARED SINCE THE LATEST MIOCENE.3. INVESTIGATING CLEARED LEAVES OF ABOUT 220 OAK SPECIES, AN IDENTIFICATION SHEME FOR THE SUBGENERA AND SECTIONS OF THE GENUS QUERCUS IS ESTABLISHED ON THE BASIS OF LEAF ARCHITECTURE. BASED ON THIS SCHEME, A NUMBER OF FOSSIL OAK LEAVES DESCRIBED FROM THE TERTIARY OF EAST ASIA ARE REDESIGNATED AS 12 SPECIES. ALL THE DECIDUOUS OAKS FROM THE EOCENE TO EARLY MIOCENE BELONG TO SECTION CERRIS AND ALBAE, AND THOSE OF SECTION ILEX, SUBER AND DENTAE APPEARED SINCE THE MIDDLE MIOCENE. HOWEVER, FOSSIL LEAVES OF CYCLOBALANOPSIS REMAINED TO BE UNSOLVED IN PHYLOGENY.4. ALL THE FOSSILS REPORTED AS THE FAGACEAE FROM THE WORLD ARE EXAMINED. THE DIVERGENCE INTO THREE SUBFAMILIES OF FAGACEAE OCCURRED IN THE PALEOCENE OR EARLY EOCENE TIME, AND THE SPECIMENS REFERABLE DOUBTLESSLY TO THE EXTANT GENERA ARE CONFIRMED FIRST IN THE LATEST EOCENE OR EARLY OLIGOCENE.