橐吾属的起源、演化与地理分布

橐吾属Ligularia Cass．是菊科千里光族款冬亚族的一个大属。在款冬亚族中本属与大吾风草属 Farfugium Lindl．亲缘关系最近,但进化程度较高。本属包括6组,11系129种。所有种类均分布在 亚洲,仅2种扩散至欧洲。在东亚地区有119种,占该属总种数的96％。高度集中在横断山区的有4组、 6系67种,其中61种为特有种,占该属总组数的66％,总系数的54．5％,总种数的52％。这个事实 表明了横断山区是该属的多度中心和多样化中心。通过性状分析,伞房组伞房系Sect．Corymbosae, Ser．Calthifoliae叶肾形,具掌状叶脉,头状花序大而少,排列呈伞房状,总苞半球形,被认为是该属的 原始类群。原始种齿叶橐吾L. dentata和鹿蹄橐吾L.hodgsonii的分布区从我国四川东部经过湖北、湖 南、安徽、福建等省至日本。这个分布格局与近缘属大吴风草属Farfugium一致。 根据共同起源原理,这两个属的祖先极有可能就发生在这一地区。因此我们推测东亚地区从中国四 川东部至日本这一地区是本属的发源地,然而根据地质历史和现代分布,作者认为中国中部(包括四川 东部)是本属的初始起源地。该属起源后,基本上沿亚洲南缘的山地扩散,少数种类向东北至亚洲东北部。本属起源时间至少不晚于中白垩纪。     

A Study on Dichocarpum (Ranunculaceae)

The genus Dichocarpum was established by W. T. Wang and Hsiao in 1964, who divided the genus into 2 sections: Sect. Dichocarpum including 10 species distributed on the mainland of E. Asia, and Sect. Hutchinsonia including 9 species native to Japan. M. Tamura and L. A. Lauener made a revision of the genus in 1968, who divided the genus into 4 sections, three for the species of the mainland of E. Asia, including 3 series and 10 species, and the other for the species of Japan, including 2 subsections, 3 series and 9 species. In the present paper, the genus is divided into 2 sections and 6 series, including 15 species and 3 varieties, and a putative phylogeny of the genus is proposed. The genus may be close to the genus Asteropyrum, and these two genera are rather specialized in Thalictroides (Ranunculaceae), because they have three very similar characters: the petal with a long claw, the stephanocolpate pollen and the chromosome morphology. The genus has 2n=24, 35(36?), which indicates that its basic number is X=6, and the species on the mainland of E. Asia (Sect. Dichocarpum) may well be paleotetraploids, whereas those in Japan (sect. Hutchinsonia) are paleohexaploids. Most of the advanced species are distributed in Japan and the most primitive ones in China and the Himalayas, the distribution pattern seggests that the Japanese members of this genus might have immigrated from China in the Tertiary, and differentiated and evolved there. The putative phylogeny of the genus is shown in Fig. 2 (at series level)     

The Origin,Dispersal and Formation of the Distribution Pattern of Swertia L. (Gentianaceae)

The genus Swertia is one of the large genera in Gentianaceae, including 154 species, 16 series and 11 sections. It is disjunctly distributed in Europe, Asia, Africa and N. America, but entirely absent from Oceania and S. America. According to Takhtajan’s (1978) regionalization of the world flora, Swertia is found in 14 regions. Eastern Asiatic region with 86 species, of which 58 are local endemics, 13 series and 9 sections, ranks the first among all the regions. The highest concentration of the taxa and endemics in Eastern Asiatic region occurs in SW China-Himalayan area (Sikang-Yunnan P. , W. Sichuan, W. Yunnan-Guichou Plateau of China and NE. Burma, N. Burmense P. , E. Himalayan P. and Khasi-Manipur P. ). In this area there are 74 species (48 endemics), 12 series, and 9 sections; thus about half species of the world total, three quarters of series and 82% of sections occur in this small area. Besides, the taxa at different evolutionary stages in Swertia also survive here. It is an indication that SW. China-Himalayan area is a major distribution centre of the genus Swertia. In addition, Sudan-Zambezian Region in Africa, with 22 species, 4 series and 2 sections, is a second distribution centre. The primitive type of the genus Swertia is Sect. Rugosa which consists of 2 series and 23 species. It is highly centred in the mountains of SW. China (Yunnan, Sichuan, Guizhou and SE. Xizang) where 2 series and 16 species occur. Among them 15 species of Ser. Rugosae were considered as the most primitive groups in this genus. From our study, the outgroup of Swertia is the genus Latouchea Frahch. , which is distributed in Yunnan, Sichuan, Guizhou, Hunan, Guangdong, Guangxi and Fujian. The two groups overlap in distribution in SW. China. According to the principle of common origin, the ancestor of two genera ap peared most probably in this overlapping area. It was inferred that SW. China Was the birth-place of the genus Swertia. Four sections of Swertia have different disjunct distribution patterns: Sect. Ophelia is of Tropic Asia, Africa and Madagascar disjunct distribution; sect. Swertia is of north temperate distribution; sect. Spinosisemina is in Tropical Asia (Trop. India to S. China and Philipines); sect. Platynema also is in Tropical Asia (Java, Sumatra, Himalayas to SW. China). These disjunct patterns indicate that the Swertia floras between the continents or between continent and islands have a connection with each other. From paleogeographical analysis, Swertia plants dispersed to Madagascar before the Late Cretaceous, to SE. Asian Islands in the Pleistocene, to North America in the Miocene. The distribution of Swertia in Madagascar might be later than that in Asia. Therefore the origin time of the genus Swertia was at least not later than the Late Cretaceous, and might be back to the Mid-Cretaceous. The genus Swertia first fully developed and differentiated, forming some taxa at different evolutionary stages (Rugosa, Swertia, Poephila, Ophelia and Platynema etc. ) in the original area, and these taxa quickly dispersed in certain directions during the Late Cretaceous-Middle Tertiary when the global climate was warm and no much change. There seem to be three main dispersal routes from the origin area to different continents; (1) The westward route i. e. from SW. China, along the Himalayas area to Kashmir, Pakistan, Afghanistan and Iran, and then southwestwards into Africa throuth Arabia. Four sections (Poephila, Macranthos, Kingdon-Wardia and Ophelia) took this dispersal route. Most species of sect. Ophelia dispersed along this route, but a few along southern route and north ern route. Sect. Ophelia greatly differentiated in Africa and the African endemic sectionSect. Montana was derived from it. The two sections form there a second distribution center of Swertia. (2) The southward route, i. e. towards S. India through the Himalayas, and towards SE. Asian islands through C. and S. China, Indo-China. Along this dispersal route sect. Platynema, Sect. Spinosisemina and a few species of Sect. Ophelia dispersed; (3) The northward rout, i. e. northwards across N. China, C. Asia to a high latitude of Euasia, and also through E. Asia into N. America. The following groups took this route: sect. Rugosa, sect. Swertia, sect. Frasera, sect. Heteranthos and sect. Ophelia ser. Dichotomae. Therefore, it seems that the genus Swertia originated in SW. China and then dispersed from there to N. and S. Asia, Africa, Europe and North America and formed the moderndistribution pattern of this genus.     

The Classification and Distribution of Genus Deutzia in China

Discussed in the present paper are evolutionary trends of important morphological characters of Deutzia, systematic position of several closely related genera, geographical distribution and characteristics of floristic elements. Finally the classificatory revison of the genus is made and a key to species is given. As a result, evolutionary trends of the important morphological characters in Deutzia are suggested; petals from imbricate to valvate, stamens from indefinite to definite, filaments from edentate to dentate, ovary from half-inferior to inferior. Therefore, the section Neodeutzia with valvate corolla and infinite stamens with edentate filaments should be included in this genus. The sections Neodeutzia and Mesodeutizia seem to be better considered as primitive taxa, while the section Deutzia advanced one. There are 52 species of Deutzia in China , which are grouped into two sections ( Sect. Mesodeutzia, Sect. Deutzia), four subsections (Subsect. Deutzia, Subsect. Grandiflorae, Subsect. Stenosepalae, Subsect. Cymosae)and 17 series. Sixty- five species are so far recognised in the genus Deutzia. They are mainly distributed in E. Asia and disjunctively in N. America. China is therefore an area the richest in species of Deutzia in the world, making up 80% of the total species of this genus. The greatest concentration area is in Sichuan (23 species), Yunnan (21 species), Hubei (12 species) and Shanxi (10 species), this is boundary area between Sino-Himalayan subregion and Sino-Japanese subregion, where occur abundant species (including 39 endemic species) and diverse taxa (2 section and 4 subsection). Based on these facts it is proposed that the present center of distribution and differentiation of Deutzia be in the southern part of the Hengduan Mountains, the Qingling Range and C. China.     

大吴风草属、假橐吾属花粉表面纹饰及其分类学意义

观察了千里光族款冬亚族中大吴风草属,假橐吾属及其相关类群5属共8种植物在扫描电镜下的花粉性状,所有种类的花粉外壁均为刺状纹饰,但在刺的长短,刺部是否膨大、刺基膨大上的纹饰以及刺基之间的纹饰等方面存在差别,大吴风草的花粉外壁性状不同于橐吾属,从而不支持它与后者有较近亲缘关系的观点它与花粉超薄结构同为“向日葵型”的多榔菊属的花粉外壁性状也不相同,假橐吾属不同于橐吾属和垂头菊属的花粉外壁性状,研究结果支持本单种属的成立。     

从鄂西木林子自然保护区种子植物区系的地理分布论川东-鄂西地区的区域性特征

本文研究了鄂西木林子种子植物区系的地理分布,并探讨了川鄂山地的区域性特征。木林子区系现知种子植物共134科、488属、约1043种(包括种下分类单位,下同)。本区系10个东亚特有科中有6科的分布边界止于川鄂山地,3科盛产于川鄂山地。约141属的分布区明显集中于川鄂山地或以川鄂山地为其主要分布区之一,约占该区系488属的28.9%。有52属的分布边界限于川鄂山地,另有27个百种以上大属的分布在川鄂山地呈急剧减少的态势。本区系以川鄂山地为主要分布区的有131种,占全部种数的12.56%,其中仅分布于川鄂山地的就有36种;还有约270种的分布边界止于川鄂山地。川鄂山地独特生境的阻限和对植物种系发生的诱发作用,是形成这种地理分布格局的重要原因。     

Distribution of Willows (Salix) in China

The distribution of willows in China is studied in this paper. The origin of this genus and its distribution in the world are also discussed. There are 255 species of willows in China, taking up 46% of the total number of species of this genus in the world. They belong to 37 sections, which represent almost all forms. China is therefore the richest area in species and sections of willows in the world. This is mostly caused by the uplifting of Qinghai-Xizang (Tibet) plateau. The willows in China are mainly distributed in northwestern, northeastern and southwestern regions. The northwest is a part of central Asian flora. The northeast is a part of northeastern Asian flora. They both have some of the Europe-Siberia and Arctic-Alpine elements. Qinghai-Xizang plateau is another important distribution center of willows, which has no close relation with other floristic regions. As one of typical genera of the Holarctic flora, Salix has probably originated in the tropical mountains of Southeast Asia.     

安息香科的系统位置及地理分布

安息香科为柿目的一成员,包括１１个属,为一自然的分类群．它与山茶科很接近,并可能是从它的祖先类群演化而来的．本文分析其形态特征的演化趋势,认为子房上位,花冠裂片覆瓦状排列,雄蕊为花冠裂片两倍,花序圆锥花序为原始性状,而子房下位．花冠裂片镊合状排列,雄蕊与花冠裂片的同数,花序少花或单花为进化性状．安息香属为本科最大的属,形态变异多样化,既具有最原始性状,为本科原始类群代表,同时又有较多进化性状．其他各属可能是以它作为基干演化而来．从分析各属的分布区类型,本科有７属分布于热带地区,但仅有３属真正分布于热带,其余４属分布于亚热带或其边缘地区．因此,安息香科基本上是一个热带科,但不典型,它可能是从古热带山区的亚热带地区演化而来的．根据全科的属和种的统计,有１１属,１５０余种,间断分布于欧亚和美洲两大陆块上,亚洲有１０属,５７种,主要分布于东亚,在这一地区,以我国秦岭和长江以南至南岭以北及华西南种类最丰富,包括有最原始类群和系统演化各阶段类群;热带南美洲有２属８３种,这一带种类虽丰富,但仅２属及缺乏原始类群．因此,我们称东亚为安息香科的分布和分化中心,而热带南美洲为第二分布中心．根据化石记载结合本科现代分布格局,我们     

A Conspectus of the Genus Bergenia Moench

In this paper the classification of the genus Bergenia Moench is provided, its geographic distribution analysed, and the phylogeny also traced. Based on an analysis of morphological characters such as leaves, ocreas, branches of inflorescences, Pedicels, hypanthium, sepals, and glandular indumentum, thi genus is divided into 3 sections: 1. Sect. Scopulosae J. T. Pan, sect. nov., 2. Sect. Bergnia, 3. Sect. Ciliatae (A. Boriss.) J. T. Pan, stat. nov. The Sect. Scopulosae J. T. Pan may be considered as the primitive one, while Sect. Ciliatae (A. Boriss.) J. T. Pan may be regarded as the advanced one, with Sect. Bergenia in between. So far, the genus Bergenia Moench comprises 9 species in the total. Southeast Asia and North Asia (south and east Siberia, USSR) each have only 1 species, West Asia (Afghanistan) has 2, Central Asia (Kirghizia-Tajikistan-Uzbekstan area, USSR) 3, South Asia 4 (Nepal has 4, India, Pakistan and Kashmir area each has 3, Bhutan and Sikkim each has 2), East Asia 6. In East Asia, Mongolia and Korea each have only 1 species, but China has 6 (including endemic species 2 and new species 1). Sichuan Province and Xizang Autonomous Region each have 3, Yunnan Province 2, Shaanxi Province (Qinling Mountains) and Uygur Autonomous Region of Xinjiang each have only 1. Thus the distribution centre of this genus should be in the region covering Sichuan, Yunnan and Xizang. Moreover, it is noteworthy that Bergenia scopulosa T. P. Wang in Sect. Scopulosae seems to have retained primitive characters, for example, non-ciliate leaves and ocreas, glabrous pedicels, hypanthium and sepals, and this primitive species is found in Qinling Mountains and Sichuan. According to the distribution of the primitive species, the author suggests that the centre of origin of this genus be in the region covering Qinling Mountains and Sichuan.     

青藏高原跳甲亚科昆虫区系研究

讨论青藏高原（包括横断山区）的跳甲亚科昆虫区系。该区已知47属228种。1）据属级阶元的分布类型分析,以东洋属和南型属种显占优势,是区系主体,显示该区跳甲区系的热带渊源,其中高山属种赋予该区以高山区系特征;2）该区物种分化活跃,是某些多种属中国种类的分布中心和分化中心;3）联系中国跳甲亚科区系,在地理分布格局上显示西－东分布,如Hespera属的分布和西南－东北分布或西南－东北的间断分布格局,如Pentamesa和Stenoluperus属的分布。这种地理分布格局反映青藏高原的隆起给中国昆虫区系带来重要影响。     

四川牻牛儿苗科(Geraniaceae)植物地理分布的研究

四川牛儿苗科植物共3属、53种、2变种, 其中老鹳草属Geranium49种, 2变种, 牛儿苗属Erodium2种, 熏倒牛属Biebersteinia2种。属的分布区类型分别为世界分布, 地中海区至温带、热带亚洲、大洋洲至南美洲间断分布和地中海区、西亚至中亚分布。研究了本科植物在四川的水平分布和垂直分布情况。水平分布方面, 在东部四川盆地及盆周山地分布着老鹳属1属、23种、2变种, 占四川本科种数的43%。在西部, 川西南河谷山原地区分布着老鹳草属植物32种, 占四川儿苗科植物总数的60%, 是四川老鹳草属植物分布最集中的地区。在川西北随着地理纬度的升高, 属的数目逐渐增加, 到最北面, 3属均产, 但老鹳草属植物的种类则逐渐减少。垂直分布方面, I、川东盆地及川西南山 地常绿阔叶林地带有老鹳草属1属、44种、2变种, 占四川供牛儿苗科植物总数 83%, 主要分布在川西南河谷山原植被地区。П、川西高山峡谷山原针叶林地带, 分布着老鹳草属和优牛儿苗属植物25种, 占四川本科植物的47%, 主要分布在川西 高山峡谷区。III、四川北高山灌丛、草甸地带, 分布着老鹳草属、狀牛儿苗属和熏 倒牛属植物12种。熏倒牛属在四川仅分布在这一地带内。     

A Study on the Genus Rubus of China

The genus Rubus is one of the largest genera in the Rosaceae, consisting of more than 750 species in many parts of the world, of which 194 species have been recorded in China. In the present paper the Rubus is understood in its broad sense, including all the blackberries, dewberries and raspberries, comprising the woody and herbaceous kinds. So it is botanically a polymorphic, variable and very complicated group of plants. The detailed analysis and investigation of the evolutionary trends of the main organs in this genus have indicated the passage from shrubs to herbs in an evolutionary line, although there is no obvious discontinuity of morphological characters in various taxa. From a phylogenetic point of view, the Sect. Idaeobatus Focke is the most primitive group, characterized by its shrub habit armed with sharp prickles, aciculae or setae, stipules attached to the petioles, flowers hermaphrodite and often in terminal or axillary inflorescences, very rarely solitary, druplets separated from receptacles. Whereas the herbaceous Sect. Chamaemorus L. is the most advanced group, which is usually unarmed, rarely with aciculae or setae, stipules free, flowers dieocious, solitary, druplets adhering to the receptacles and with high chromosome numbers (2n = 56). Basing upon the evolutionary tendency of morphological features, chromosome numbers of certain species recorded in literature and the distribution patterns of species, a new systematic arrangement of Chinese Rubus has been suggested by the present authors. Focke in his well-known monograph divided the species of Rubus into 12 subgenera, while in the Flora of China 8 sections of Focke were adapted, but some important revisions have been made in some taxa and Sect. Dalibarda Focke has been reduced to Sect. Cylactis Focke. In addition, the arrangement of sections is presented in a reverse order to those of Focke’s system. The species of Rubus in China are classified into 8 sections with 24 subsections (tab. 3) as follows: 1. Sect. Idaeobatus, emend. Yü et Lu(11 subsect. 83 sp.); 2. Sect. Lampobatus Focke (1 sp.); 3. Sect. Rubus (1 sp.); 4. Sect. Malachobatus Focke, emend. Yü et Lu (13 subsect. 85 sp.); 5. Sect. Dalibardastrus (Focke)Yü et Lu (10 sp.); 6. Sect. Chaemaebatus Focke (5 sp.); 7. Sect. Cylactis Focke, emend. Yü et Lu (8 sp.); 8. Sect. Chamaemorus Focke (1 sp.). In respect to the geographical distribution the genus Rubus occurs throughout the world as shown in tab. 2, particularly abundant in the Northern Hemisphere, while the greatest concentration of species appears in North America and E. Asia. Of the more than 750 species in the world, 470 or more species (64%) distributed in North America. It is clearly showm that the center of distribution lies in North America at present time. There are about 200 species recorded in E. Asia, of which the species in China (194) amount to 97% of the total number. By analysis of the distribution of species in China the great majority of them inhabit the southern parts of the Yangtze River where exist the greatest number of species and endemics, especially in southwestern parts of China, namely Yunnan, Sichuan and Guizhou (tab. 3. 4.). It is interesting to note that the centre of distribution of Rubus in China ranges From northwestern Yunnan to south-western Sichuan (tab. 5), where the genus also reaches its highest morphological diversity. In this region the characteristics of floristic elements of Rubus can be summarized as follows: it is very rich in composition, contaning 6 sections and 94 species, about 66% of the total number of Chinese species; there are also various complex groups, including primitive, intermediate and advanced taxa of phylogenetic importance; the proportion of endemic plants is rather high, reaching 61 species, up to 44% of the total endemics in China. It is noteworthy to note that the most primitive Subsect. Thyrsidaei (Focke) Yü et Lu, consisting of 9 endemic species, distributed in southern slopes of the Mts. Qin Ling and Taihang Shan (Fig. 4). From the above facts we may concluded that the south-western part of China is now not only the center of distribution and differentiation of Rubus in China, but it may also be the center of origin ofthis genus.     

槭属的系统演化与地理分布

槭属（ＡｃｅｒＬ）属槭树科（Ａｃｅｒａｃｅａｅ）,２００种,分布于亚、欧、北美和非洲北缘。本文研究了槭属的系统演化、地理分布、起源与扩散。认为：（１）槭树科与无患子科关系密切,槭属是槭树科２属中较进化的类群。（２）在原始而典型的槭属植物的基础上,槭属沿花的各部减少,有的器官甚至向完全退化的方向演化,但也有少数向增加数目的方向特化。（３）讨论了槭属４亚属２３组的演化趋势,并绘制出其系统演化图。（４）槭属起源于侏罗纪的中国四川东部、湖北、湖南及其邻近地区,并向西、东北和南方扩散而进入西亚、欧洲、非洲北缘、北美洲和马来半岛至印尼。     

The phytogeographical studies of Thermopsis (Fabaceae)

The present article is the first comprehensive treatment of phytogeography of Thermopsis (Fabaceae) in the world. Thermopsis is one of the few genera within Fabaceae with the distribution pattern of the East Asia-North American disjunction. The distribution patterns of 5 recognized sections (including a new one) covering 21 species in Thermopsis are analyzed, and the results show four centres of frequency of the genus: the Eastern Asiatic Region (9 spp. / 3 sects., including 4 endemic species), the Irano-Turanian Region (7 spp./3 sects., including 3 endemic species), the Rocky Mountain Region (7 spp./2 sects., all endemic), and the Atlantic North American Region (3 spp. / 1 sect., all endemic). In the light of the fact that most species and sections, a number of phylogenetic series of the genus, and the most primitive sections and most advanced sections in Thermopsis occur in the East Asia, the Eastern Asiatic Region might be the centre of diversity of the genus. As the Irano-Turanian Region and the Rocky Mountain Region were just second to that of Eastern Asiatic Region in number of sections and species, and many polyploids appeared in these regions, they were considered as the secondary centres of distribution and speciation of the genus. The speciation looks to be frequent and complex in these regions, and many new taxa have been described from there while many new reduced or incorporated taxa have happened over there. However, recent molecular data has shown that two reduced taxa of Thermopsis are distinct in these regions. Based on the modern distribution patterns and evolutionary trends in morphological characters of the genus, and available fossil record of the genus and the historical geology, we speculate that Thermopsis had already existed on Eurasia and North America before the Late Miocene, and probably originated from an ancestral form of Sophora-like taxa with lupine alkaloids somewhere in the Laurasia in the Early Tertiary or Late Cretaceous. After the separation of the two continents, species on different continents developed distinctly under influences of different evolutionary factors. In Asia, the late Tertiary orogeny, disappearing of the Tethys and aridity and freezing caused by the Quaternary glaciation were the main forces to promote the speciation and evolutionary processes, whereas in North America it was the Quaternary glaciation and the orogeny of partial area to promote evolution of the genus. According to the evolutionary trends in Thermopsis and the distribution pattern of the primitive taxa, Sino-Japanese Subregion of Eastern Asiatic Region may be considered asthe centre of primitive forms of Thermopsis.     

A Preliminary Study on the Taxonomy of the Family Magnoliaceae

A new system of classification of Magnoliaceae proposed. This paper deals mainly with taxonomy and phytogeography of the family Magnoliaceae on the basis of external morphology, wood anatomy and palynology. Different authors have had different ideas about the delimitation of genera of this family, their controversy being carried on through more than one hundred years (Table I). Since I have been engaged in the work of the Flora Reipublicae Popularis Sinicae, I have accumulated a considerable amount of information and material and have investigated the living plants at their natural localities, which enable me to find out the evolutionary tendencies and primitive morphological characters of various genera of the family. According to the evolutionary tendencies of the characters and the geographical distribution of this family I propose a new system by dividing it into two subfamilies, Magnolioideae and Liriodendroideae Law (1979), two tribes, Magnolieae and Michelieae Law, four subtribes, Manglietiinae Law, Magnoliinae, Elmerrilliinae Law and Micheliinae, and fifteen genera (Fig. 1 ), a system which is different from those by J. D. Dandy (1964-1974) and the other authors. The recent distribution and possible survival centre of Magnoliaceae. The members of Magnoliaceae are distributed chiefly in temperate and tropical zones of the Northern Hemisphere, ——Southeast Asia and southeast North America, but a few genera and species also occur in the Malay Archipelago and Brazil of the Southern Hemisphere. Forty species of 4 genera occur in America, among which one genus (Dugendiodendron) is endemic to the continent, while about 200 species of 14 genera occur in Southeast Asia, of which 12 genera are endemic. In China there are about 110 species of 11 genera which mostly occur in Guangxi, Guangdong and Yunnan; 58 species and more than 9 genera occur in the mountainous districts of Yunnan. Moreover, one genus (Manglietiastrum Law, 1979) and 19 species are endemic to this region. The family in discussion is much limited to or interruptedly distributed in the mountainous regions of Guangxi, Guangdong and Yunnan. The regions are found to have a great abundance of species, and the members of the relatively primitive taxa are also much more there than in the other regions of the world. The major genera, Manglietia, Magnolia and Michelia, possess 160 out of a total of 240 species in the whole family. Talauma has 40 species, while the other eleven genera each contain only 2 to 7 species, even with one monotypic genus. These three major genera are sufficient for indicating the evolutionary tendency and geographical distribution of Magnoliaceae. It is worthwhile discussing their morphological characters and distributional patterns as follows: The members of Manglietia are all evergreen trees, with flowers terminal, anthers dehiscing introrsely, filaments very short and flat, ovules 4 or more per carpel. This is considered as the most primitive genus in subtribe Manglietiinae. Eighteen out of a total of 35 species of the genus are distributed in the western, southwest to southeast Yunnan. Very primitive species, such as Manglietia hookeri, M. insignis and M. megaphylla, M. grandis, also occur in this region. They are distributed from Yunnan eastwards to Zhejiang and Fujian through central China, south China, with only one species (Manglietia microtricha) of the genus westwards to Xizang. There are several species distributing southwards from northeast India to the Malay Archipelago (Fig. 7). The members of Magnolia are evergreen and deciduous trees or shrubs, with flowers terminal, anthers dehiscing introrsely or laterally, ovules 2 per carpel, stipule adnate to the petiole. The genus Magnolia is the most primitive in the subtribe Magnoliinae and is the largest genus of the family Magnoliaceae. Its deciduous species are distributed from Yunnan north-eastwards to Korea and Japan (Kurile N. 46’) through Central China, North China and westwards to Burma, the eastern Himalayas and northeast India. The evergreen species are distributed from northeast Yunnan (China) to the Malay Archipelago. In China there are 23 species, of which 15 seem to be very primitive, e.g. Magnolia henryi, M. delavayi, M. officinalis and M. rostrata, which occur in Guangxi, Guangdong and Yunnan. The members of Michelia are evergreen trees or shrubs, with flowers axillary, anthers dehiscing laterally or sublaterally, gynoecium stipitate, carpels numerous or few. Michelia is considered to be the most primitive in the subtribe Micheliinae, and is to the second largest genus of the family. About 23 out of a total of 50 species of this genus are very primitive, e.g. Michelia sphaerantha, M. lacei, M. champaca, and M. flavidiflora, which occur in Guangdong, Guangxi and Yunnan (the distributional center of the family under discussion) and extend eastwards to Taiwan of China, southern Japan through central China, southwards to the Malay Archipelago through Indo-China. westwards to Xizang of China, and south-westwards to India and Sri Lanka (Fig. 7). The members of Magnoliaceae are concentrated in Guangxi, Guangdong and Yunnan and radiate from there. The farther away from the centre, the less members we are able to find, but the more advanced they are in morphology. In this old geographical centre there are more primitive species, more endemics and more monotypic genera. Thus it is reasonable to assume that the region of Guangxi, Guangdong and Yunnan, China, is not only the centre of recent distribution, but also the chief survival centreof Magnoliaceae in the world.     

四川被子植物区系特征的初步研究

四川地区被子植物区系188科1493属8711种及1252变种,全球50％以上的科都有代表,与毗邻地区及世界植物区系有着广泛而密切的联系。区系古老而原始,珍稀孑遗类群丰富;单型或少种的科属众多,含100种以上的大科和大属也十分繁荣;含5种以下的属占76.89%,但占总属数约22.64%的多种属和大属是区系的主体,包含区系总种数的63.28%。科的分布类型有明显热带性质,属、种的分布类型反映出典型的亚热带属性。优势现象明显,特有类群和表征类群丰富。该地区被子植物区系对中国乃至东亚都有代表性。     

Cytogeographic Study of the Genus Paris

The Genus Paris L., distributed in Europe and Asia, is one of the genera of Trilliaceae. There are currently 19 recognized species. The karyological study indicates that basic number of the Paris species is X=5, and here are two kinds of the basic karyotypes: tropical type (K2n=2x=10=6m+4t), and temperate type (K2n=2x=10=6m+4st, or 6m+ 2st+2t). The species (13) with the tropical karyotype are distributed in the tropical and subtropical regions in Asia; the others with the temperate karyotype (6 species) occur in the temperate area of Eurasia. In the genus Paris, there are two peripheral species, which both have temperate karyotypes: tetraploid P. quadrifolia, in the western part of the overall range of the genus (Europe), and octaploid P. japonica, limited in the eastern part (Japan). All the species having tropical karyotypes are diploid. Among them, the more primitive ones such as P. dunniana, P. vietnamensis are concentrated in South China and the north of the Indo-China Peninsula. Examination of the geographical distribution of the species in the light of the karyological data has led the authors to propose: Paris originated in the tropical area between 18°N and 23°27’N in Asia. 14 species, which together make up 74% of the total (with 10 different karyotypes), occur in the area from the Qionglei Mountains to the Yunnan-Guizhou Plateau. With the greatest density of species in the area and their remarkable differences in chromosome ploidy and karyotypes, this region is without doubt the centre of modern distribution and differentiation of Paris.     

On the geographical distribution of the Juglandaceae

The present paper aims to discuss the geog raphical distribution of the Juglandaceae on the basis of unity of the phylogeny and the process of dispersal in the plants. The paper is divided into the following three parts: 1. The systematic positions and the distribution patterns of nine living genera in the family Juglandaceae (namely, Engelhardia, Oreomunnea, Alfaroa, Pterocarya, Cyclocarya, Juglans, Carya, Annamocarya and Platycarya) are briefly discussed. The evolutional relationships between the different genera of the Juglandaceae are elucidated. The fossil distribution and the geological date of the plant groups are reviewed. Through the analysis for the geographical distribution of the Juglandaceous genera, the distribution patterns may be divided as follows: A. The tropical distribution pattern a. The genera of tropical Asia distribution: Engelhardia, Annamocarya. b. The genera of tropical Central America distribution: Oreomunnea, Alfaroa. B. The temperate distribution pattern c. The genus of disjunct distribution between Western Asia and Eastern Asia: Pterocarya. d. The genus of disjunct distribution between Eurasia and America: Juglans. e. The genus of disjunct distribution between Eastern Asia and North America: Carya. f. The genera whose distribution is confined to Eastern Asia: Cyclocarya, Platycarya. 2. The distribution of species According to Takhtajan’s view point of phytochoria, the number of species in every region are counted. It has shown clearily that the Eastern Asian Region and the Cotinental South-east Asian Region are most abundant in number of genera and species. Of the 71 living species, 53 are regional endemic elements, namely 74.6% of the total species. The author is of the opinion that most endemic species in Eurasia are of old endemic nature and in America of new endimic nature. There are now 7 genera and 28 species in China, whose south-western and central parts are most abundant in species, with Province Yunnan being richest in genera and species. 3. Discussions of the distribution patterns of the Juglandaceae A. The centre of floristic region B. The centre of floristic regions is determined by the following two principles: a. A large number of species concentrate in a district, namely the centre of the majority; b. Species of a district can reflect the main stages of the systematic evolution of the Juglandaceae, namely the centre of diversity. It has shown clearly that the southern part of Eastern Asian region and the northern part of Continental South-east Asian Region (i.c. Southern China and Northern Indo-China) are the main distribution centre of the Juglandaceae, while the southern part of Sonora Region and Caribbean Region (i.c. South-western U.S.A., Mexico and Central America) are the secondary distribution centre. As far as fossil records goes, it has shown that in Tertiary period the Juglandaceae were widely distributed in northern Eurasia and North America, growing not only in Europe and the Caucasus but also as far as in Greenland and Alaska. It may be considered that the Juglandaceae might be originated from Laurasia. According to the analysis of distribution pattern for living primitive genus, for example, Engelhardia, South-western China and Northern Indo-China may be the birthplace of the most primitive Juglandaceous plants. It also can be seen that the primitive genera and the primitive sections of every genus in the Juglandaceae have mostly distributed in the tropics or subtropics. At the same time, according to the analysis of morphological characters, such as naked buds in the primitive taxa of this family, it is considered that this character has relationship with the living conditions of their ancestors. All the evidence seems to show that the Juglandaceae are of forest origin in the tropical mountains having seasonal drying period. B. The time of the origin The geological times of fossil records are analyzed. It is concluded that the origin of the Juglandaceae dates back at least as early as the Cretaceous period. C. The routes of despersal After the emergence of the Juglandaceous plant on earth, it had first developed and dispersed in Southern China and Indo-China. Under conditions of the stable temperature and humidity in North Hemisphere during the period of its origin and development, the Juglandaceous plants had rapidly developed and distributed in Eurasia and dispersed to North America by two routes: Europe-Greenland-North America route and Asia-Bering Land-bridge-North America route. From Central America it later reached South America. D. The formaation of the modern distribution pattern and reasons for this formation. According to the fossil records, the formation of two disjunct areas was not due to the origin of synchronous development, nor to the parallel evolution in the two continents of Eurasia and America, nor can it be interpreted as due to result of transmissive function. The modern distribution pattern has developed as a result of the tectonic movement and of the climatic change after the Tertiary period. Because of the continental drift, the Eurasian Continent was separated from the North American Continent, it had formed a disjunction between Eurasia and North America. Especially, under the glaciation during the Late Tertiary and Quaternary Periods, the continents in Eurasia and North America were covered by ice sheet with the exception of “plant refuges”, most plants in the area were destroyed, but the southern part of Eastern Asia remained practically intact and most of the plants including the Juglandaceae were preserved from destruction by ice and thence became a main centre of survival in the North Hemisphere, likewise, there is another centre of survival in the same latitude in North America and Central America. E. Finally, the probable evolutionary relationships of the genera of the Juglanda-ceae is presented by the dendrogram in the text.     

The Classification and Distribution of the Genus Calligonum L. in China

The genus Calligonum L. includes a total number of 35 species in the world, of which 24 are in China. They are grouped into four sections, of which Sect. Calliphysae (Fisch. et Mey.) Borszcz. is the most primitive and Sect. Medusae Sosk. et Alexender. is the most progressive. The Calligonum L. is an ancient genus in the arid desert flora, and central Asia is the place of its origin. Some species migrated to the Middle Asia and Iran, developing into a second center there. Also, some newly occurred species of the Middle Asia emigrated eastwards to central Asia, so the genus Calligonum L. in China comprises components of both central Asia and the Middle Asia. The genus Calligonum L. is distributed in North Africa, south Europa and Asia, and China is the eastmost part of the distribution range. They grow in Nei Monggol, Gansu, Qinghai and Xinjiang. There are 12 species in the Zhuengar Basin, covering 50 percent of the total number of species in China, amd thus the genus is the most abundant there.