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1.
本文采用薄层层析和提取、分离、光谱分析等方法分析研究了三尖杉属植物叶的双黄酮类化合物，根据获得的化学分析结果，我们同意：(1)将三尖杉属分为二个组：篦子三尖杉组Sect．1 Pectinaea，只包括蓖子三尖杉一种；三尖杉组Sect．2 Cephalotaxus，包括本属所有其它种。(2)支持三尖杉科只包括三尖杉属1属，不支持将红豆杉科中的穗花杉属(Amentotaxus)归入三尖杉科的主张。(3) 认为三尖杉科与南洋杉科、松科、杉科和柏科的亲缘关系较远，而与红豆杉科及罗汉松科的亲缘关系密切。 相似文献
2.
中国主要禾本科植物花的基本类型与系统分类 总被引：1，自引：0，他引：1
本文研究、分析了禾本科33个族、174个属(632种)的花的性状；讨论了重要性状演化
的趋势。根据花、尤其花中鳞被的比较形态，把禾本科植物的花概括为三大类型七个亚型：竹
型(包括真竹亚型，稻亚型、芦竹亚型、针茅亚型)、早熟禾型(含早熟禾亚型)和黍型(包括画眉
草亚型，真黍亚型)。其结果与花的基本类型相对应的大类群，以及与幼苗基本类型、颖果基本
类型相对应的大类群是一致的，即竹亚科、稻亚科、芦竹亚科、针茅亚科、早熟禾亚科、画眉草亚 科，黍亚科。 相似文献
3.
通过构建分子钟对广义柏科主要分类群的起源时间进行探讨。采用相对速率检验法分析广义柏科mat K、rbc L进化速率的稳定性，结果显示rbc L的非同义替代速率只在Pinaceae与Taxodiaceae的分类群及柏科北半球的支系(Cupressoideae)之间通过相对速率检验，而Pinaceae与柏科南半球分支(Callitrodeae)之间没有通过相对速率检验。mar K基因的非同义替代速率在Pinaceae与广义柏科的所有分类群之间通过相对速率检验。根据通过相对速率检验的分类群之间的遗传距离和基因进化速率，计算它们发生分歧的时间。据此推测，杉科的主要分类群Taiwanioideae、Athrotaxidoideae、Sequoioideae与其他分支发生分歧的时间均在侏罗纪，支持现存杉科在侏罗纪就已经建立起来的观点；Cupressaceae(s．s．)的两个支系(亚科)发生分歧的时间在124Ma之前，相当于早白垩世早期，可能由于南北古大陆的完全分离，其祖先居群被分隔成两个亚群，随后各自演化为不同的支系。Callitirodeae、Cupressoideae各属发生分歧的时间也均在白垩纪，表明Cupressaceae(s．s．)在白垩纪就已经建立起来。 相似文献
4.
台湾杉属Taiwania包括秃杉T．flousiana Gaussen和台湾杉T.cryptomerioides Hayata 两种。秃杉现已列为我国一级国家重点保护植物。本文作者在光学显微镜和扫描电镜下，系统 观察了秃杉营养苗端，叶角质层内、外表面及叶子内部结构，幼茎，茎的次生韧皮部和次生木质 部的结构等。通过对秃杉各营养器官形态结构的观察，并结合有关文献资料，同杉科其它各属作了比较分析，我们不赞同将台湾杉属提升为一个单型科——台湾杉科的主张，而支持Hayata (1906；1907)早期提出的关于台湾杉属应作为杉科中的一个属，其系统位置可介于密叶杉属与杉木属之间的观点。 相似文献
5.
陈之端 《中国科学院研究生院学报》1991,29(6):494-503
对桦木科植物(包括6属36种)的花粉进行了光学显微镜、扫描电镜和透射电镜观察；系统地描
述了各属的花粉形态，划分了三种花粉类型，即桦木型、榛型、鹅耳枥型，并澄清了前人在带状加厚、孔盖和颗粒层等概念上的模糊认识。根据花粉的形态，作者不支持Hutchinson(1973)和Dahlgren(1983)把桦木科分成两个科，即榛科(包括榛属、虎榛子属、鹅耳枥属和铁木属)和桦科(包括桤木属和桦木属)；而同意Abbe(1974)将桦木科作为三个族来处理，并且认为虎榛子属应该从榛族分出，置于鹅耳枥族；尽管作者不支持Kuprianova(1963)将桦木科划分为三个科，但本文所提出的三个族与Kuprianova的三个科只是分类等级上的差异。 相似文献
6.
通过扫描电镜对国产水鳖科植物(包括6属13种)的种皮微形态特征进行观察，并作了系统描述。根据种皮细胞形态、外种皮表面纹饰和内种皮内层小瘤状突起的特点将水鳖科植物的种皮微形态特征划分为3种类型，即海菜花型(海菜花属)、水鳖型(水鳖属)和苦草型(苦草属、水筛属、虾子草属和黑藻属)，并作出了分属检索表。本文结果表明，种皮微形态特征可作为该科族、属以及属内种级水平分类的依据，对探讨属间关系和该科的系统发育关系亦具有重要的价值。种皮微形态特征支持Hutchinson(1959)和Eckhardt(1964)将海菜花属和水鳖属分别作为一个独立的族处理的观点。苦草属、水筛属和虾子草属种皮微形态特征的高度相似性表明它们间有密切的联系，不支持将它们置于不同亚科和族的分类处理。黑藻属虽与上述3属近缘，但其外种皮特征则较为独特，因此与水筛属放在不同族中更为合理。本文种皮微形态特征的研究结果支持iki1937)和Shaffer-Fehre(1991b)等关于水鳖科与茨藻科近缘的观点。 相似文献
7.
四合木属Tetraena Maxim． 是内蒙古自治区西部和亚洲中部荒漠区东部的特有属，也是珍稀
濒危植物。前人曾对该属的系统地位做过一些研究，但观点不一。作者通过对该属的研究历史、雌蕊、
果实、花粉粒、染色体等的综合研究后，建议将该属从TaxTaЛЖЯН系统(1987)蒺藜科的霸王亚科中分
出，成立一个新亚科——四合木亚科。本文还编写了蒺藜科(狭义的)分亚科检索表。 四合木属的系统
地位是：芸香目蒺藜科四合木亚科四合木属。 相似文献
8.
李林初 《中国科学院研究生院学报》1990,28(1):1-9
本文根据核型资料提出杉科可能存在A、L两条演化路线，前者包括由原始到进化的柳杉属、水
松属、落羽杉属、台湾杉属，以平均臂比快速增加、染色体长度比缓慢增加为特征；后者包括依序进化的水杉属、巨杉属、红杉属、杉木属(可能还有密叶杉属)，以平均臂比缓慢增加、染色体长度比迅速增加为特点。该结论也得到形态学、解剖学、胚胎学等资料的支持。 相似文献
9.
用SDS聚丙烯酰胺凝胶电泳分析了杉科全部10属共13种植物的种子蛋白多肽。它们
都有分子量为32、24和10K(千道尔顿)的多肽。每个分类群一般只有2至4个主要多肽，构
成种子蛋白总含量的一半;而且其分子量都分布在24—26K及29—36K两个区域内。 因此，
杉科植物种子蛋白谱与红豆杉科、三尖杉科相似，而不同于松科。属内不同种之间，种子蛋白
组成和针叶过氧化物酶电泳谱都没有看到显著差别。根据这两种蛋白质资料，表明杉科各属除红杉、巨杉、落羽杉相互很接近外，其他各属间关系都比较远。但是还不能说杉科可以分立几个科。 相似文献
10.
桦木科植物叶表皮的研究 总被引：6，自引：0，他引：6
本文利用光学显微镜及扫描电镜观察了桦木科6属、38种植物的叶表皮。发现该科植物成熟叶片的气孔器有四种类型：即无规型、轮列型、不典型辐射型和短平列型，叶表皮性状及性状状态对于桦木科植物属的确定和族的划分具有重要的分类学价值。在确定叶表皮性状的演化趋势时，综合了其他方面的研究成果(如Abbe，1935，1974；Brunner和Fairbrothers，1979；Hall，1952；Kikuzava，1982；Kuprianova，1963)，并且发现叶表皮形态对于揭示桦木科植物的属间演化有较大的参考价值。作者认为：叶表皮特征支持将桦木科分成两个族；气孔器无规则型、气孔器外拱盖单层、气孔器在保卫细胞极区无”T”型加厚以及下表皮细胞垂周壁平直为原始的叶表面性状；下表皮细胞垂周壁具波纹和气孔器为不典型辐射型等特征仅发现于榛属、虎榛子属，铁木属和鹅耳枥属，从而将榛族与桦木族分开；桦木族包括桦木属和桤木属，由于具有较多的原始性状而比榛族原始，在榛族中，鹅耳枥属最为特化(见图1)。 相似文献
11.
在扫描电镜下观察了分布于南半球的柏科Cupressaceae单种属Pilgerodendron u
viferum及其相关类群的代表种Austrocedrus chilensis、Libocedrus plumosa和Papuacedr
us papuana叶角质层内外表面的微形态特征。发现Pilgerodendron uviferum叶角质层外表面
光滑，不具Florin环，而其余3个属的代表种均有明显的Florin环;且仅L.plumosa叶角质层外
表面有乳状突起。观察结果支持传统的观点，即将P.uviferum作为独立的属;不支持基于DNA
分析的结果，即将P.uviferum归并到Libocedrus属。发现Papuacedrus papuana叶角质层外表
面有许多明显的小凹陷，与其相对应的叶角质层内表面有凹陷的小狭缝，该性状以前未见报
道。 相似文献
12.
论胡桃科植物的地理分布 总被引：1，自引：0，他引：1
路安民 《中国科学院研究生院学报》1982,20(3):257-274
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, Cyclo-
carya, Juglans, Carya, Annamocarya and Platycarya) are briefly discussed. The evolu-
tional 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 distribu-
tion 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, Platy-
carya.
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 Coti-
nental 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 Pro-
vince 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 Juglanda-
ceae 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, Engelhar-
dia, 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 cha-
racters, 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 moun-
tains 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 tempera-
ture and humidity in North Hemisphere during the period of its origin and development,
the Juglandaceous plants had rapidly developed and distributed in Eurasia and dis-
persed 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 forma-
tion.
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 con-
tinents of Eurasia and America, nor can it be interpreted as due to result of transmis-
sive 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 con-
tinental drift, the Eurasian Continent was separated from the North American Conti-
nent, it had formed a disjunction between Eurasia and North America. Especially, under
the glaciation during the Late Tertiary and Quaternary Periods, the continents in Eu-
rasia 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. 相似文献
13.
方振富 《中国科学院研究生院学报》1987,25(4):307-313
1. The distribution of Salix species among the continents. There are about
526 species of Salix in the world, most of which are distributed in the Northern Hemisphere
with only a few species in the Southern Hemisphere. In Asia, there are about 375 species, mak-
ing up 71.29 percent of the total in the world, including 328 endemics; in Europe, about 114
species, 21.67 percent with 73 endemics; in North America, about 91 species, 17.3 percent with
71 endemics; in Africa, about 8 species, 1.5 percent, with 6 endemics. Only one species occurs
in South America. Asia, Europe and North America have 8 species in common (excluding 4
cultivated species). There are 34 common species between Asia and Europe, 14 both between
Europe and North America and between Asia and North America, 2 between Asia and Africa.
Acording to the Continental Drift Theory, the natural circumstances which promoted speciation
and protected newly originated and old species were created by the orogenic movement of the
Himalayas in the middle and late Tertiary. Besides, the air temperature was a little higher in
Asia than in Europe and North America (except its west part) and the dominant glaciers were
mountainous in Asia during the glacial epoch in the Quaternary Period. Then willows of Eu-
rope moved southwards to Asia. During the interglacial period they moved in opposite direc-
tion. Such a to-and-fro willow migration between Asia and Europe and between and North
America occurred so often that it resulted in the diversity of willow species in Asia. Those
species of willows common among the continents belong to the Arctic flora.
2. The multistaminal willows are of the primitive group in Salix. Asia has 28 species of
multistaminal willows, but Europe has only one which is also found in Asia. These 28 species
are divided into two groups, “northern type” and “southern type”, according to morphology of
the ovary. The boundary between the two forms in distribution is at 40°N. The multistami-
nal willows from south Asia, Africa and South America are very similar to each other and
may have mutually communicated between these continents in the Middle or Late Cretaceous
Period. The southern type willows in south Asia are similar to the North American multista-
minal willows but a few species. The Asian southern type willows spreaded all over the conti-
nents of Europe, Asia and North America through the communication between them before the
Quaternany Period. Nevertheless, it is possible that the willows growing in North America
immigranted through the middle America from South America. The Asian northern type mul-
tistaminal willows may have originated during the ice period.
The multistaminal willows are more closed to populars in features of sexual organs. They
are more primitive than the willows with 1-3 stamens and the most primitive ones in the ge-
nus.
3. The center of origin and development of willows Based on the above discussion it is re-
asonable to say that the region between 20°-40°N in East Asia is the center of the origin and
differentiation of multistaminal willows. It covers Southern and Southwestern China and nor-
thern Indo-China Pennisula. 相似文献
14.
马兜铃科的地理分布及其系统 总被引：1，自引：0，他引：1
马金双 《中国科学院研究生院学报》1990,28(5):345-355
马兜铃科基本是一个热带科。 东亚的横断山至华南一带是其原始分布与分化中心，热带美洲是其次生分布与分化中心。科的形态演化趋势是花被由分化的双被到不分化的单被，由分离到合生，由杯状到管状；雄蕊由多数到少数，由分离到与雌蕊结合成为合蕊柱；于房由半下位到完全下位；果实由蓇葖状蒴果到蒴果。马兜铃科分2亚科4族6属。 相似文献
15.
木兰科分类系统的初步研究 总被引：10，自引：0，他引：10
刘玉壶 《中国科学院研究生院学报》1984,22(2):89-109
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. mega-
phylla, 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 primi-
tive, 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, an-
thers 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. 相似文献
16.
本文根据植物类群的系统发育和地理分布相统一的原理,讨论了“低等”金缕梅类植物的起
源和散布。 “低等”金缕梅类植物(Endress1989a的概念)包括下列7科：昆栏树科、水青树科、连香
树科、折扇叶科、领春木科、悬铃木科和金缕梅科。 该类群共有13种分布区类型,东亚区的南部和
印度支那区的北部是它的现代分布中心;根据化石证据及原始类群和外类群的分布分析,以上地区最
有可能是这类植物的起源地。 “低等”金缕梅类植物起源的时间至少可追溯到早白垩纪巴列姆期,较可
靠的化石证据说明悬铃木类植物在早白垩纪阿尔必晚期出现,而昆栏树科、水青树科、连香树科和金
缕梅科植物的出现均不晚于晚白垩纪。 最后,从环境变迁和生物演化两个方面探讨了“低等”金缕梅类植物现代分布格局的形成原因。 相似文献
17.
1) The Compositae in Tibet so far known comprise 508 species and 88 genera,
which nearly amounts to one fourth of the total number of genera and one third of the
total number of species of Compositae in all China, if the number of 2290 species and 220
genera have respectively been counted in all China. In Tibet there are all tribes of Com-
positae known in China, and surprisingly, the large tribes in Tibetan Compositae are
also large ones in all China and the small tribes in Tibet are also small ones in all China.
Generally speaking, the large genera in Tibet are also large ones in all China and the
small genera in Tibet are likewise small ones in all China. In this sense it is reasonable to
say that the Compositae flora of Tibet is an epitome of the Compositae flora of all China.
In the Compositae flora of Tibet, there are only 5 large genera each containing 30
species or more. They are Aster, Artemisia, Senecio, Saussurea and Cremanthodium. And
5 genera each containing 10—29 species. They are Erigeron, Anaphalis, Leontopodium,
Ajania, Ligularia and Taraxacum. In addition, there are 77 small genera, namely 87%
of the total of Compositae genera in Tibet, each comprising 1—9 species, such as Aja-niopsis, Cavea and Vernonia, etc.
2) The constituents of Compositae flora in Tibet is very closely related to those of
Sichuan-Yunnan provinces with 59 genera and 250 species in common. Such a situation
is evidently brought about by the geographycal proximity in which the Hengtuang Shan
Range links southeastern and eastern Tibet with northern and northwestern Sichuan-
Ynnnan. With India the Tibetan Compositae have 59 genera and 132 species in common,
also showing close floristic relationships between the two regions. Apparently the floris-
tic exchange of Compositae between Tibet and India is realized by way of the mountain
range of the Himalayas. The mountain range of the Himalayas, including the parallel
ranges, plays a important role as a bridge hereby some members of the Compositae of
western or northern Central Asia and of the northern Africa or of western Asia have
migrated eastwards or southeastwards as far as the southern part of Fibet and northern
part of India, or hereby some Compositae plants of eastern and southeastern Asia or
Asia Media have migrated northwestwards as the northern part of Central Asia.
Some of the species and genera in common to both Tibet and Sinjiang indicate that
this weak floristical relationship between these regions is principally realized through two
migration routes: one migration route is by way of the Himalayas including the parallel
ranges to Pamir Plataeu and Tien Shan, or vice versa. The other migration route is by
way of northern Sinjiang to Mongolia, eastern Inner Mongolia, southwards to Gansu,
Qinghai (or western Sichuan), eastern Tibet up to the Himalayas, or vice versa.
However, Tibet is not entirely situated at a migration crossroad of the floral ele-
ments. An ample amount of the data shows that Compositae flora have a particular
capability of development in Tibet. of the total number of species of Tibetan Com-
positae, 102 species and 1 genus (Ajaniopsis Shih) are endemic. Besides, 8 genera are re-
gional endemics with their range extending to its neighbourhood. The higher percentage
of endemics at specific level than at generic in Tibetan Compositae may be a result of
active speciation in response to the new enviromental conditions created by the uplifting
of the Himalayas. The flora in Tibetan Plateau as a whole appears to be of a younger
age.
3) The uprising of the Himalayas and of the Tibetan Plateau accompanied by the
ultraviolet ray radiation, the microthermal climate and the high wind pressure has, no
doubt, played a profound influence upon the speciation of the native elements of Tibetan
Compositae. The recent speciation is the main trend in the development of the Com-positae flora native in Tibet in the wake of upheaval of the plateau. 相似文献
18.
松柏类植物叶子的比较解剖观察 总被引：3，自引：0，他引：3
本文系统地比较观察了松柏类植物7科、37属、103种8变种的叶子表皮
及内部结构特征，并记述了各属(或组)的特征，及作了分属(或组)检索表。
观察结果表明，为便于分属鉴定，Laubenfels的叶型划分，可作为第一级分
类特征。此外叶子表皮结构，皮下层的有无与排列方式，叶肉分化与否，具维管
束鞘或内皮层，转输组织类型，维管束的数目与空间相对位置，树脂道的数目及
位置，以及石细胞或厚壁组织细胞的存在与否等特征，在属一级中较为稳定，可
作为各属分类的重要依据。
柏科各属(刺柏属与圆柏属除外)均属鳞叶(叶型Ⅲ)，其结构特征差异甚
少，不易区分。
本文还讨论了树脂道，具凯氏带的内皮层，厚壁组织以及维管束等在分类鉴 定上的价值问题* 相似文献