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1.
本文报道了黑龙江依兰煤矿早第三系始新统达连河组的上、下两个层位所产的植物化石的区系组成及植物群特征：一个系产于煤层下部的砂页岩中的植物群A，另一个是产于煤层上部油页岩中的植物群B。植物组合共计35科49属52种，其中有蕨类植物2种，裸子植物10种，被子植物40种，其中包括1个新种。对其进行区系成分和叶相分析表明，A段植物群的古植被为北亚热带常绿阔叶和落叶阔叶混生林；B段植物群的古植被为暖温带落叶阔叶林。通过与邻近地区的国内外相应植物群比较及植物群的属种地史分布分析，确定A段植物群的时代为早始新世，B段植物群的时代很可能为晚始新世。两个层位间植物群区系成分的变化，表明始新世我国东北地区发生了较明显的气温下降过程，即古气候发生了由亚热带向暖温带的变化。 相似文献
2.
本文是北部湾东北部、雷州半岛、涠洲岛及海南岛北部十几口钻井中涠洲组
孢粉工作的总结。在涠洲组中共见113种孢粉类型，其中大部分为欧亚及北美
第三纪、尤其是渐新世孢粉区系成分，同时也出现加里曼丹岛渐新世-早中新世
区系的一些重要分子。这表明沉积时期本地区与加里曼丹岛有陆地相通或在地
理位置上较今日为近，植物能相互迁移。 印度第三纪孢粉区系与涠洲组区系相
似性拉少，仅出现少数相似类型(水蕨孢子、松科花粉)，说明虽然自印度次大陆
与欧亚大陆相遇后，这两地区的植物有了相互迁移的可能，但是直到渐新世，这
种迁移的规模还是很有限的，迁移到印度的植物所产生孢粉类型在印度发展的
高峰可能较欧亚大陆为晚。
从孢粉所反映的生态条件看，陆生及淡水植物多，而海产植物(如红树林)及
藻类很少。这说明当时北部湾可能为陆地，与雷州半岛等地连成一个内陆凹陷。
大量温带及山地针叶植物花粉及少量热带低地植物花粉的出现表明本地区附近
曾有大面积山地。 从孢粉组合上看，涠洲组形成的时代为渐新世。 相似文献
3.
本文着重讨论山豆根属植物的分类、分布、系统亲缘及起源等问题。对本属的分类历史和”山豆
根”一名的由来作了回顾和考证．按中国古典植物文献，”山豆根’指的是Euchresta japonica 。
我们对山豆根属进行一次清理，在本文共报道4种3变种，其中发现一新变种——短管山豆根
Ｅ.tubulosa Dunn var.brevituba C.Chen，井以萼管的有无建立I.山豆根组sect．I．Euchrestae(3种1变
种)及II．管萼组sect．II．Tubulosae(1种2变种)。
山豆根属的现代分布中心在我国中部及南部，可能是第三纪或略早一些的古热带山地森林植物区
系的成员。推测本属可能出现于晚白垩纪，可能是华夏起源。本属的分布区正好处于 “华莱士线”的西
侧，从古地理的资料告诉我们大约在五千万年前，新几内亚和澳大利亚还处在向北移动的状态，这时本
属已遍布东亚和东南亚地区，因此，新几内亚和澳大利亚等地没有本属的分布，这一分布格局正好又一
次证明，在这一地区的诸多的生物地理分界线中，”华莱士线’更符合自然，使我们更清楚的认识到”华莱
士线”的实际意义不仅是劳亚古陆与冈瓦纳古陆的分界线，而且还是亚洲与澳大利亚地区劳亚古陆植物区系与冈瓦纳古陆植物区系的分界线。 相似文献
4.
黑龙江晚白垩世植物区系及东亚、北美区系的关系 总被引：5，自引：0，他引：5
本文记载了黑龙江嘉荫县乌云组所产植物化石，计有53种，隶属39属、28科。其中蕨
类植物7种，裸子植物8种，被子植物38种(包括单子叶植物1种)，10个种为新种。
乌云组植物化石的区系及植被的分析结果表明，在植物区系成分中，大多是亚热带至暖温
带分子，具少数温带成分，由此组成的群落有暖性针叶林，落叶阔叶林和常绿阔叶林等，共同组
成暖性针阔叶混交林，指示当时气候温暖潮湿，大约是暖温带向亚热带过渡的气候特点。再从
植物化石叶子外貌特征来分析，其中全缘叶占40％; 叶的体积以中型的占大多数，大型和小型
的均少数; 脉序以具掌状脉的占多数。这些特征说明，沉积时期亦为温暖潮湿的气候。
晚白垩世在东亚出观的35属化石中，其中27属和北美共有，约占总属数的77％，这种区
系组成的相似程度，表明其区系具有密切的亲缘关系。这种亲缘随着时间的推移，在进入第三
纪或向更晚发展的进程中而逐渐减弱。主要由于大陆漂移和板块运动，使欧亚、北美在第三纪
初完全分离，此后这两块大陆隔离发展，植物区系的相同分子逐渐减少，以至现在生存植物中
的相同属仅占总数的4．1％，其中草本植物还占有相当大的比例。
根据我国东北地区晚白垩纪所产植物化石及同时代南方所产化石，大致可把晚白垩世的
植物区(带)划分为三个：(1)暖温带至亚热带植物区，主要代表植物是Metasequoia，Trochoden-
droides，Platanus，Ampelopsis，Protophyllum，Pterospermites，Menispermites; (2)亚热带至热
带植物区，植物有Brachyphyllum，Cinnamomum，Nectandra和棕榈科植物; (3)亚热带或干
旱植物区，兼有南北过渡的植物或呈干旱性的植物。
乌云组植物大化石共有33属，和东亚，北美同时代植物群对比，出现不少相同属种，其中
15个属种出现在苏联晚白垩世的察加扬组及东锡霍特阿林，11个属种出现在日本晚白垩世
的Kuji地区，若与加拿大晚白垩世植物群比较,有11个相同属种; 与阿拉斯加晚白垩世植物
对比，则有12个相同属种; 若与乌云组同属一区的太平林场组比较，相同属种更多。再从孢粉
组合成分看，和本区松辽盆地明水组相同的属有15个，并具有少数晚白垩世代表性的花粉如
鹰粉、沃氏粉和山龙眼粉，表明乌云组的时代和明水组接近。同时在乌云组大化石中绝灭类型约占70％，证实该植物群的古老性。其时代属于马斯特里赫特期至达宁期而不是古新世。 相似文献
5.
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
6.
吴竞标 《大科技．科学之谜》2004,(1):21-21
喜马拉雅海何以变为万仞高山?自6500万年前以来的新生代,随着印度古陆与欧亚大陆碰撞挤压,古地中海东部和喜马拉雅海逐渐封闭,喜马拉雅山的雏形开始出现。在5000万年前的新生代早期,喜马拉雅山主体的北部仍有残留的浅海,到了3750万年前,由于著名的喜马拉雅造山运动,喜马拉雅地区的海水全部退出,从而结束了它那漫长的海洋历史。其后,喜马拉雅山主体上升为陆地,在最近的300万年中,喜马拉雅山迅速上升,总计上升了约3000米,平均每一万年上升10米。而最近的一万年来,它却上升了700米,即一年上升7厘米,至今它还在以不易被人觉察的速度缓慢上升呢!… 相似文献
7.
一、资源概况 我国幅员辽阔,自然地理条件复杂。各地的自然环境差异很大,由于自然历史条件的综合影响,全国植被种类很多。东半部的森林植被有针叶林、针阔混交林、阔叶混交林(含常绿、落叶成分)、常绿阔叶林、热带雨林、季雨林和竹林;其它植被有灌丛、稀树灌丛草原、草甸、草原等。西部地区除针叶林外,大都属于森林草原、草原、草甸、荒漠等植被类型。在植物资源中,全国有高等植物近3万种,其中近200个属的植物为我国所特有,如银杉、水杉、金钱松、白豆 相似文献
8.
本文讨论了西藏波密古乡地区的主要植物群落及其垂直分布。
1．根据小带间植物种类相似系数情况，将波密古乡地区南、北坡划成八个植物垂直带
(图1)。
2．描述了七个不同性质的植物群落。各群落分布与水热条件之间的相互关系如图2所
示。 3．由于不同水热条件的影响，各植被带间在植物种数上的差异是比较显著的(表3)。 相似文献
9.
羌塘与拉萨地块处于青藏高原的核心位置。青藏高原北羌塘及拉萨地块的年代学及古地磁学研究表明,北羌塘地块在距今约3亿年前位于南半球(21.9o±4.7oS)冈瓦纳大陆附近,因而不支持北羌塘地块来自北方劳亚大陆。北羌塘随后开始其持续的北向漂移过程,在约2.1亿年前到达当前纬度位置(34oN),形象地表明其是一只"冈瓦纳大陆的早飞鸟"。拉萨地块从冈瓦纳大陆裂离后的漂移演化史则与北羌塘地块差别明显。自晚古生代—中生代(石炭纪—三叠纪)拉萨地块从冈瓦纳大陆北缘裂离后,其运动学演化过程更显得"犹豫不决"。最新的古地磁研究表明拉萨地块自冈瓦纳大陆裂离后并未显示出明显的快速北向漂移趋势,而是呈现出较为慢速的漂移,直到距今约1.8亿年前(早侏罗世)到达位于南半球赤道附近(3.7o±3.4oS),随后与北面的羌塘地块在晚侏罗世首先从东部发生碰撞,随后于早白垩世时期两个地块完成拼贴。之后的印度次大陆快速向北漂移并在早新生代(距今6 500万年前)发生印度-亚洲大陆碰撞,继而对新生代时期欧亚大陆地形地貌格局产生了深远影响。 相似文献
10.
西藏的马先蒿属植物及其来源与演化的探讨 总被引：1，自引：0，他引：1
杨汉碧 《中国科学院研究生院学报》1982,20(1):23-33
本文对西藏地区马先蒿植物的分类、演化、地理分布和来源进行了初步探
讨。
1．本属植物种类在西藏非常丰富，有108种，为全国总种数的33%。其中
特有种35个，占总种数的35．9%。这一特点在藏东南地区表现尤为明显，这里
拥有全西藏82．7%。的种类和88%。的特有种。
2．从花、叶征状与演化关系来看，在藏东南地区具有从原始的互生叶无齿类
型和对生叶有齿类型到有喙、有管的进化花冠类型，而且在演化上是非常活跃的。
3．这里出现几乎各种形态类型的花粉，尤以独特类型的三沟、原始的三合沟
占绝对优势。而且具进化类型的二合沟花粉的种几乎全是有喙、长管花的类型，
二者之间的进化趋势和相关性十分明显。
综合上述特征，可以认为藏东南地区是本属植物的演化中心。
4．根据毗邻地区的区系地理研究，认为西藏的马先蒿属植物主要来源于东
部的川西、滇西北高原边缘山地，至于与其它地区如不丹、尼泊尔，和我国新疆、
青海、甘肃的关系是不密切的，共同种类多系广布种。
我国西藏自治区位于青藏高原西南部，周围为喜马拉雅山脉，昆仑山脉和唐古拉山脉
所环绕，幅员辽阔，地势高亢，是世界上最高最大，而且在地质史上最年轻的高原的主体。
高原及其边缘山地这一独特而复杂的自然环境，对于这个地区植物的地理分布和系统发
育有极其深刻地影响，在这些研究领域内具有特殊的意义。 本文试图就编写西藏植物 志［1］过程中，接触到的马先蒿属植物来源与演化问题提出一些浅见。 相似文献
11.
The Rosaceae is one of the five largest families of Xizang flora, consisting of
30 genera with 242 species, the total number of species is slightly less than those of
Compositae, Graminae, Leguminosae and Ericaceae in Xizang, amounting to 62.5% of
the total number of genera and 28% of the total number of species of the rosaceous flora
in China.
The four subfamilies of Rosaceae including primitive, intermediate and advanced
groups have been found in Xizang. These groups consist of 11 types of floristic ele-
ments, i.e. 4 genera belong to cosmopolitan, 9 genera belong to North Temperate, 3, E.
Asian-N. American, 3 Sino-Himalayan, 3 Sino-Japanesa, 2 Old World Temperate, 1
Temperate Asian, 2 Mediterranean-W. and O. Asian, 1 C. Asian, I Tropical Asian and 1
endemic to China. It is obvious that Rosaceae in Xizang comprises holarctic, Ancient Me-
diterranean and paleotropical elements, among which the temperate components are the
most dominant. The characteristics of the floristic composition of Rosaceae in Xizang
may be summarized as follows:
(1) Xizang abounds in both genera and species of the family which are diverse in
forms, including the primitive, intermediate and advanced groups, (2) The geographi-
cal elements are rather complex, mostly belonging to the temperate, among which the
Sino- Himalayan components and the elements endemic to China are dominant, (3) The
proportion of plants endemic to China and distributed in Xizang is much higher than
those endemic to Xizang itself, but there exist newly arisen species and infraspecific
forms or varieties which show that the speciation is apparently still active in Xizang.
The rosaceous flora of Xizang is a combination of old and new floristic elements, based
on the old floristic components, affected by the upheaval of the Himalayas, the differen-
tiation and speciation have been taking place in the long history.
The geographical distribution of Rosaceae in Xizang may be divided into 5 regions,
i.e. the northeastern, southeastern, southern, northwestern and northern. The rosaceous
plants are most abundant in the southeastern area, next in southern area, fewer in the
northeastern and very rare in the northwestern and northern regions. The general ten-
dency of the distribution of Rosaceae in Xizang is that the number of species gradually
decreases from the southeast to the northwest and the habit gradually changes from
trees, shrubs and herbaceous plants in the southeast to cushion-like scrubs and dwarf
perennial herbs in the northwest. These facts clearly show that the uplift of the Hi-
malayas has deeply affected the phytogeographical distribution of Xizang Rosaceae.
The rosaceous flora of Xizang has close relationships with those of the adjoring
regions, i.e. Yunnan and Sichuan. Besides, it is connected with floras of Nepal, Sikkim,
Bhutan nothern Buram and nothern India, but silghtly influenced by the Ancient Medi-
terranean flora. 相似文献
12.
中国第三纪植被和植物区系历史及分区 总被引：5，自引：0，他引：5
陶君容 《中国科学院研究生院学报》1992,30(1):25-42
被子植物的发展(或称辐射)是与古气候、古地理环境密切相关的，诸因素的变化相互影响及制
约，形成植物发展的阶段性。这种阶段变革及划分与传统的地质时代划分——断带，不尽一致，因而讨论
植物地理分区问题应以发展的不同阶段为基础，致使分区更为合理。
在晚白垩纪中晚期，被子植物已成为植物区系中的优势成分，从它出现以来的发展演化大致可划分
为四个阶段：(1)初始期 被子植物初次出现，具有叶形小、叶边全缘、叶脉缺乏规律性、脉级分化程度低
等原始性特点，同时在区系中的种数及个体数量均为极少数，此时大约在早白垩纪的中晚期；(2)极盛时
期被子植物发展具有一定规模至占绝对优势，此时叶形增大，叶脉有了规律性，脉级分化逐渐完善，在
植物区系中所占比例达40％一60％，以致占绝对优势，主要科属出现了，时间在晚白垩至老第三纪；(3)
草本植物繁盛阶段 由于在新第三纪时气候逐渐转凉，早期的一些木本植物消灭了，以草本植物渐增多
至大量扩散为特点，时间约在中新世至上新世；(4)第四纪阶段 此时我国由于山岳冰川随全球性气候
冷暖变化而进退，影响植物的分布及发展，植物区系的总面貌与现代接近或略有差别。 本文亦重点讨论了植物发展的第二、第三阶段的植物地理分区。 相似文献
13.
张明理 《中国科学院研究生院学报》1997,35(2):136-147
锦鸡儿属Caragana是一个典型的温带亚洲分布属。本属在青藏高原和喜马拉雅约有24种1变种，约占整个属的1／3。这些种类几乎全部处于演化高级阶段，且既有叶轴宿存类群，也有假掌状叶类群。反映出种的分化很活跃，在横断山地区形成本属的分布中心、分化中心。本区内绝大多数种类是特有分布。替代现象主要受气候、植被变化作用，沿横断山和喜马拉雅分布的长齿系Ser. Bracteolatae Kom．是一个典型的替代分布类群。锦鸡儿属植物生态适应性很强，可在其生长的灌丛中形成优势种。 寒化和旱化现象十分突出，它们有一系列森林种、草原种和荒漠种及相关的形态变异。用锦鸡儿属植物进行青藏高原和喜马拉雅区域内的分布区关系分析及最小生成树MST和特有性简约性分析(PAE)，表明横断山地区特别是其北部是本属植物的一个地理结点。以此沿横断山向北部唐古特和西部藏东南适应性辐射。横断山和西喜马拉雅联系微弱，看不出植物长距离扩散的踪迹，大多是由于生态因子限制而产生的隔离。虽然本区不可能是锦鸡儿属的起源地，然而，通过本区与邻近地区的地理联系，可推测它们在我国适应性辐射方向是从东北向西南。结合豆科蝶形花亚科其它属化石记录及其分布区局限在温带亚洲等现象，认为锦鸡儿植物是一组特化、晚近衍生的类群，起源于北方东西伯利亚晚第三纪中新世后期至上新世。 相似文献
14.
The present paper deals with a collection of plant fossils from the Wu-
yun Group of Heilongjiang Province. These fossils belong to 28 families, 39 genera
and 53 species. The flora is composed of 7 species of pteridophytes, 8 of conifers and 37
of angiosperms. All have been fully described, of which ten are new species.
Most elements of this flora are subtropic or warm-temperate, with only a few of
them are temperate ones. The flora consists of conifers and broad-leaved trees adapted
to humid warm-temperate or subtropic climate.
With the physiognomy of leaves, 40 per cent of them are of entire margin, and most
are medium-sized, with some megaphyllous. The nervation is mostly palmate. These
characters indicate that the climate was warm-temperate or subtropic.
Among 35 genera known from the Late Cretaceous of East Asia, 27 are also found
in North America, which indicates that the floristic relationship between East Asia and
North Americal was closer at that time than it is now. Therefore the number of
genera in common has been decreasing through the age, because these two regions have
been detached from each other since the late Eocene, as a result of continental drift.
Only some relic forms left on both sides, and only 4.1% of genera are common to both
continents. After the early Tertiary the floras of East Asia and North America have
been developing independently.
The Chinese flora of the Late Cretaceous may be divided into three Zones from the
north to the south: (1) warm temperate-subtropic zone, rich in Metasequoia, Ginkgo,
Trochodendroides, Platanus, Trochodendron, Protophyllum, Ampelopsis Pterospermites
and Menispermites; (2) subtropic or dry subtropic transitional zone; and (3) subtropic-
tropic zone, rich in Brachyphyllum, Cinnamomum, Nectandra and Palms.
The Wuyun flora is considered closely related to the Chajiayang Group and Sikhote-
Alin flora of USSR, with 15 genera in common and also related to the Kuji flora of
Japan (Cenonian), with 11 genera in common. It is interesting to note that 11 genera
are also found in North America (Canada and Alaska) of the Late Cretaceous. The pa-
lynological assemblage of the Wuyun flora is closely related to Minshui flora of the So-
uliao Basin, 15 genera being common to the both. Seventy per cent of megafossils of
the Wuyun flora have become extinct, which seems to show that the age of the flora is
older than Paleocene and is assigned to the Latest Late Crataceous (Maestrichtian-Dani-an). 相似文献
15.
我国荒漠植物区系形成的探讨 总被引：2，自引：0，他引：2
刘媖心 《中国科学院研究生院学报》1982,20(2):131-141
1. Based upon the analyses in the floristic elements of the three genera (Suaeda,
Salsola and Zygophyllum) in different regions we can see that the genesis of our desert
floras in these regions is very much diversified. The flora of Songaria is similar to that
of the Middle Asia, while the Hosi Corridor seems to be a transitional area very close to
Alashan and also related to the Tarim Basin in floristic elements. Thus, we may classify
the desert floras into three parts: the flora of Songaria, of Alashan including the Hosi
Corridor and of the Tarim Basin including the Tsaidam Basin. The ages and approa-
ches in their formation are different.
2. There are plenty species but no or rare endemics in Songaria. In spring there
are a number of ephemeral plants. The variation of aspect is evident. The vegetation
cover is abundant. The floristic elements are developed from the flora of Middle Asia
and it was formed in Quaternary period.
3. The floristic elements of the Tarim Basin are poor, but there are not few en-
demics and the distribution of the endemics is much limited. They are of the charac-
teristics of relic species. Therefore it was formed in the Tertiary period and developed
in Quaternary period. The elements are related to the Mediterranean flora.
4. There are a large number of endemics and many endemic monotypie genera in
Alashan. They represent the flora formed in Tertiary period. Although it is of a special
style, it relates both to the Middle-Asian and the Mediterranean flora.
5. The historic causes for the formation of the different floras lie chiefly on: (1)
The rise of the Tibetan plateau and mountains strongly changed the climatic and edaphic
conditions and in the long course of evolution some species survived or even developed,
while the others deteriorated or even died out from the flora. (2) Because the circum-
stances of transgression or regression of the Tethys were different in these regions. (3)
The mountain-making movement, the transgression and regression and the fluence of
glaciation, all the mutation of these associated factors modified the climatic zonation and
then the plant species changes followed, new species formed and migration of floristie
elements occurred. (4) Songaria is the nearest region to the then Sibirian glacier, so the
frozen injury to the flora might be the greatest. (5) In the Glacial period the descension
of snow line in Songaria was greater than that of the Tarim Basin, so the frozen injurymight be greater. 相似文献
16.
The Xizang (Tibetan) flora with numerous endemics is of importance in Chi-
nese flora. According to recent statistics there are in Xizang 27 genera of spermatophytes
endemic to China, being only 2.25% percent of the total number of genera in the Xizang flora.
Four of them are regarded as palaeoendemics (14.81%) and the others as neoendemics (85.19%).
These endemic genera, of 30 species and 3 varieties, belong to 17 families, of which, Umbelli-
ferae contains 6 genera, 7 species and 3 varieties; Compositae has 6 genera and 7 species, and
Gentianaceae 1 genus and 2 species. All the other families each comprises one genus with a
single species.
The cosmopolitan families together comprising 14 genera with 15 species have the highest
perecentage (52.92%) and the tropical ones (5 families, 5 genera with 5 species) come to the next
(29.42%), followed by the temperate ones (3 families, 10 genera with 10 species) (17.66%). It
shows that these endemic genera are obviously related to the tropical flora and temperate one
in essence.
According to the number of species, the genera endemic to China and occurring in Xi-
zang flora may be grouped as fallows.
Monotypic endemic ones 14 (51.85%)
Ditypic endemic ones 6 (22.22%)
Oligotypic endemic ones 4 (14.81%)
Small endemic ones 3 (11.11%)
The formation of the endemic genera is correlated with the topography, climate and en-
vironmental conditions, and they may have resulted from the diversification in geography and
climatic influence for a long time. The southeastern part of Xizang Plateau is of very diverse
ecological conditions, with the adequate precipitation, which may explain the concentration of
these endemic genera in this region.
The largest similarity coefficient (38.30%) of the genera endemic to China and occurring
in Xizang is with those in Qinghai Plateau, next, with those in Yunnan and in Sichuan pro-
vinces (both 27.60%), which shows that these endemic genera are related to the floras of the
regions mentioned above.
The difference in the horizontal distribution of these endemic genera is obviously between
the southern and northern parts of Xizang Plateau. The vertical distribution of the genera is
also rather obvious, from 800 m to 5200 m above sea level, but concentrated in the zone of 3000
m to 4500 mm. Therefore their occurrence in Xizang is not only affected by the historical
environmental conditions but also controlled by the horizontal and vertical distribution.
The origin and evolution of some endemic genera, such as Psammosilene, Parateropyrum,
Sphaerotylos, Salweenia, Ajaniopsis, Xizangia, Sinoleontopodium, are discussed in this paper.
Parateropyrum, a monotypic palaeotropic endemic, belongs to the tribe Atraphaxideae in-
cluding Atraphaxis, Calligonum and Pteropyrum. It may be a comparatively advanced group
in the tribe, and is closely related to the genus Pteropyrum which is distributed in western
Asia. The genus Parapteropyrum has possibly survived as a palaetropic-tertiary relic in this
region.
Sphaerotylos, a member of the subtribe Sphaerotylinae, the tribe Boehmerieae in the family
Urticaceae, is a comparatively primitive genus in the tribe Boehmerieae so far known. As the
other subtribes, such as Boehmerinae, Sarconchlamydinae, Orecnidinae and Maoutinae, are dis-
tributed in the tropics, rarely in the subtropics, the genus is no doubt a palaetropic -tertiary
relic.
Sinoleontopodium, belonging to the tribe lnuleae in Compositae, is also related to the ge-
nus Leontopodium. It is probable that the genus Sinoleontopodium arised later than the other.
We come to the conclusion that the southern part of Xizang Plateau is also one of thecentres of the origin and differentiation of genera endemic to China. 相似文献
17.
湘西北壶瓶山自然保护区植物区系 总被引：1，自引：0，他引：1
壶瓶山自然保护区具有丰富的植物区系成分，现知维管束植物有205科(蕨类和拟蕨类 植物40科，裸子植物7科，被子植物158科)，839属，约1961种(包括154变种)。其中，古 和原始的科、属不乏其代表。从种子植物属的分布区类型的比较分析，该区具有我国15个种子植物属的分布区类型中的14个，表明了与世界各地区植物区系的联系程度。另一方面，该 地区的植物区系虽含有丰富的热带成分，但根据各类温带属占该区总属数的百分比以及分布于该地区的中国特有属中的木本属几乎所有都是落叶的乔木或灌木，该区的植物区系性质明显偏重于温带性质。而且，这种温带性质可能与该区的山体海拔高度有着重要的联系。 相似文献
18.
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
19.
中国柳属植物地理分布的研究 总被引：2，自引：0，他引：2
赵士洞 《中国科学院研究生院学报》1987,25(2):114-124
本文研究了中国产柳属植物的分布，并探讨了该属的起源与演化问题。 我国产柳
属植物255种，约占全世界总数的46％，隶属于37个组，几乎包括了该属所有的进化类型。
因此，中国是世界柳属植物种数最多、类型最丰富的地区。青藏高原的出现，是形成这一分布
特点的重要原因。我国柳属植物主要分布在西北、东北和西南地区。西北地区是中亚分布区
的一部分; 东北地区是东北亚分布区的一部分; 它们又都有一些中欧-西伯利亚和北极-高山成
分。青藏高原与其他分布区间的联系很少，是柳属又一个重要的分布中心。作为泛北极植物
区系的典型属之一的柳属，可能起源于东南亚热带山区。 相似文献