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1.
中国重庆毛茛科银莲花属一新种——涪陵银莲花   总被引:1,自引:0,他引:1  
描述了中国重庆市涪陵区的毛莨科Ranunculaceae银莲花属Anemone一新种——涪陵银莲花A.fulingensisW.T.Wang&Z.Y.Liu,并绘出墨线图。根据此新种的总苞苞片无柄,花具4-5枚萼片,花丝丝形,花粉具散沟等特征,可以确定此种应是属于银莲花属鹅掌草组Anemone sect.Stolonifera的一个成员;在该组中,此种以其独特的由2-10个块茎组成的念珠状根状茎而与该组的其他种相区别。鉴于在银莲花属中块茎出现于不同的演化路线中,以及这些块茎的出现系次生现象,可见此新种应是鹅掌草组的进化种。  相似文献   

2.
Pollen organization and morphology of the South American Chloraeinae (Orchidaceae) was examined by scanning electron microscopy and compared with that of the remainder of the otherwise Australasian Diurideae. All five genera of the Chloraeinae, Bipinnula, Chloraea, Codonorchis, Gavilea, and Geoblasta, and at least one genus from each of the other subtribes were sampled. The Australasian Diurideae are diverse in pollen organization and morphology. The two genera of the Acianthinae, Corybas and Acianthus, have very different pollen and their classification is questioned. Monad pollen organization of Pterostylis (Pterostylidinae) is reinterpreted as primitive and not secondarily derived. Pollen of the Chloraeinae is uniform in exine morphology and organization. Most species sampled have reticulate pollen which tends to be foveolate distally. The basic pollen unit of all Chloraeinae is the tetrad, except Codonorchis which possesses monads. Pollen morphology and organization of the Chloraeinae is most similar to the Caladeniinae, which supports the contention that the Chloraeinae including Codonorchis should be retained in the Diurideae.  相似文献   

3.
A particular pollen type is observed in the species Euphorbia caputmedusae which is distributed in South Africa. The exine of this pollen is clearly rugulose and beset with coarse granules. In addition 10 to 25% of the pollen grains are heteropolar and have a characteristic aperture type which is something between tricolporate and parasyncolpate. The pollen morphology of this species gives grounds for suggesting its removal from the section Euphorbium to a separate section, as suggested by Carter (1988).  相似文献   

4.
The biogeography of Gunnera L.: vicariance and dispersal   总被引:2,自引:1,他引:1  
Aim The genus Gunnera is distributed in South America, Africa and the Australasian region, a few species reaching Hawaii and southern Mexico in the North. A cladogram was used to (1) discuss the biogeography of Gunnera and (2) subsequently compare this biogeographical pattern with the geological history of continents and the patterns reported for other Southern Hemisphere organisms. Location Africa, northern South America, southern South America, Tasmania, New Zealand, New Guinea/Malaya, Hawaii, North America, Antarctica. Methods A phylogenetic analysis of twenty‐six species of Gunnera combining morphological characters and new as well as published sequences of the ITS region, rbcL and the rps16 intron, was used to interpret the biogeographical patterns in Gunnera. Vicariance was applied in the first place and dispersal was only assumed as a second best explanation. Results The Uruguayan/Brazilian Gunnera herteri Osten (subgenus Ostenigunnera Mattfeld) is sister to the rest of the genus, followed sequentially upwards by the African G. perpensa L. (subgenus Gunnera), in turn sister to all other, American and Australasian, species. These are divided into two clades, one containing American/Hawaiian species, the other containing all Australasian species. Within the Australasian clade, G. macrophylla Blume (subgenus Pseudogunnera Schindler), occurring in New Guinea and Malaya, is sister to a clade including the species from New Zealand and Tasmania (subgenus Milligania Schindler). The southern South American subgenus Misandra Schindler is sister to a clade containing the remaining American, as well as the Hawaiian species (subgenus Panke Schindler). Within subgenus Panke, G. mexicana Brandegee, the only North American species in the genus, is sister to a clade wherein the Hawaiian species are basal to all south and central American taxa. Main conclusions According to the cladogram, South America appears in two places, suggesting an historical explanation for northern South America to be separate from southern South America. Following a well‐known biogeographical pattern of vicariance, Africa is the sister area to the combined southern South America/Australasian clade. Within the Australasian clade, New Zealand is more closely related to New Guinea/Malaya than to southern South America, a pattern found in other plant cladograms, contradictory to some of the patterns supported by animal clades and by the geological hypothesis, respectively. The position of the Tasmanian G. cordifolia, nested within the New Zealand clade indicates dispersal of this species to Tasmania. The position of G. mexicana, the only North American species, as sister to the remaining species of subgenus Panke together with the subsequent sister relation between Hawaii and southern South America, may reflect a North American origin of Panke and a recolonization of South America from the north. This is in agreement with the early North American fossil record of Gunnera and the apparent young age of the South American clade.  相似文献   

5.
Two species of dispersed pollen (Tubuliforidites antipodica and T. viteauensis) that have affinity with the Asteraceae were recovered from Paleocene-Eocene sediments of South Africa. This is the earliest unequivocal record of the Asteraceae. The two species were examined with light, scanning, and transmission electron microscopy. The pollen wall structure of both taxa are of the Anthemoid type, a pollen wall structural type considered to be primitive among asteraceous pollen. The wall structure type is indicative of many taxa of the Mutisieae. The appearance of this pollen type in the Paleocene-Eocene of South Africa supports a early Tertiary, west Gondwana origin of the Asteraceae, and the evolutionary basal position of the Mutisieae.  相似文献   

6.
One of the traditional enigmas in freshwater zoogeography has been the evolutionary origin of Scleropages formosus inhabiting Southeast Asia (the Asian arowana), which is a species threatened with extinction among the highly freshwater-adapted fishes from the order Osteoglossiformes. Dispersalists have hypothesized that it originated from the recent (the Miocene or later) transmarine dispersal of morphologically quite similar Australasian arowanas across Wallace's Line, but this hypothesis has been questioned due to their remarkable adaptation to freshwater. We determined the complete nucleotide sequences of two mitochondrial protein genes from 12 osteoglossiform species, including all members of the suborder Osteoglossoidei, with which robust molecular phylogeny was constructed and divergence times were estimated. In agreement with previous morphology-based phylogenetic studies, our molecular phylogeny suggested that the osteoglossiforms diverged from a basal position of the teleostean lineage, that heterotidines (the Nile arowana and the pirarucu) form a sister group of osteoglossines (arowanas in South America, Australasia, and Southeast Asia), and that the Asian arowana is more closely related to Australasian arowanas than to South American ones. However, molecular distances between the Asian and Australasian arowanas were much larger than expected from the fact that they are classified within the same genus. By using the molecular clock of bony fishes, tested for its good performance for rather deep divergences and calibrated using some reasonable assumptions, the divergence between the Asian and Australasian arowanas was estimated to date back to the early Cretaceous. Based on the molecular and geological evidence, we propose a new model whereby the Asian arowana vicariantly diverged from the Australasian arowanas in the eastern margin of Gondwanaland and migrated into Eurasia on the Indian subcontinent or smaller continental blocks. This study also implicates the relatively long absence of osteoglossiform fossil records from the Mesozoic.  相似文献   

7.
Abstract—Cyttaria Berkeley (Cyttariaceae, Cyttariales, Class Discomycetes), is a genus of eleven species, seven from South America and four from Australasia (Australia, Tasmania, and New Zealand). Cyttaria is a monophyletic genus defined by the following synapomorphies: fleshy to gelatinous stromata with endostromatic apothecia; and complete lack of fungal chitin in the cell walls, having instead β-1–3-glucan. All Cyttaria are exclusive parasites of Nothofagus species. A cladistic analysis of the genus was performed using 18 characters from macromorphology, micro-morphology, and phenology. Polarity of characters is based on the outgroup comparison method (using the Class Discomycetes as a whole) and on the ontogenetic criterion. A hypothetical outgroup was constructed using all plesiomorphic states. Two equally parsimonious cladograms were produced, each with 40 steps and a consistency index of 0.70. These differed in the position of the South American species C. hookeri and C. johowii. In one cladogram, C. hookeri is the sister group to the rest of the genus, and in the other, both species form a monophyletic group (ascospores ovoid) that is the sister group of the rest of the genus. Our analysis of the two characters causing this difference (position of apothecia on stroma, and shape of ascospores) supports the latter hypothesis. In both cladograms, all of the Australasian species form a monophyletic group (thick ectostroma), and, within that, two subgroups are defined: C. gunnii-C. pallida (papillae present), and C. nigra-C. septentrionalis (ectostroma with black incrustations). The Australasian species form a monophyletic group (spermatangia absent) with C. berteroi , and this last group forms a monophyletic group (conidia absent) with C. espinosae. Cytlaria darwimi and C. exigua form another monophyletic group (very thick ectostroma). Excluding C. hookeri and C. johowii, C. hariotii is the sister group to the remaining eight species.  相似文献   

8.
The Centridini has almost 176 species distributed mainly in the tropic regions of America. Although they are considered key pollinators in the maintenance of many vegetal species, data about their bionomics are restrict. Nesting activity is known for 11 species, out of the 21 that are considered pollinators of murici, Byrsonima crassifolia L. Kunth, a valuable biomonitoring specie. A study of the nesting biology of Centris flavifrons (Friese) was conducted in the state of Maranh?o, Brazil, during the active period of the adults (May through December). Nests were aggregated. The females excavated their nests on flat surfaces of hard soils. Fifteen nests were dug and we only found cells in six of them. The nests architecture consisted of a single unbranched tunnel, with only one cell in the vertical position at the end, which was 25 cm to 50 cm away from the entrance. Nocturnal activity was observed in the nests building. The pollen analysis of the contents of four cells allowed to identify 23 floral species, six of them Malpighiaceae. Six floral species were registered visiting C. flavifrons by the first time: Lecythis lurida (Miers) Mori, Hymenea courbaril L., Myrcea sp., Protium sp., Tetrapterys sp. and Thalisia sp.  相似文献   

9.
Scanning and electron microscopic studies of the pollen grains of several species of the sub-Saharan African and Madagascan genus Aristea of c . 50 species, supplement data from an earlier study and enable us to include these species in a phylogenetic analysis. TEM examination of a range of pollen grains of representative pollen types in Aristea makes it possible to reinterpret past SEM results so that apertures covered with exine masses and previously called sulculate, are now seen to be either zonasulculate or dizonasulculate. Revised and expanded data are combined in a matrix together with new data for seed morphology in the genus, which like the capsules is remarkably diverse, including angular seeds with reticulate sculpturing, lamellate or triangular-columnar seeds with smooth or reticulate surfaces and with smooth or papillate or areolate margins. This new phylogenetic analysis suggests that Aristea should remain treated as comprising three subgenera. In subgenus Eucapsulares we add a new section Latifolieae for A. latifolia , which seems an isolated relic restricted to the mountains of the Cape Region of South Africa, an area of winter rainfall. Species with similar unspecialized capsule and seed morphology occur only in eastern south and tropical Africa and Madagascar, but they have derived pollen morphology whereas the pollen of A. latifolia is plesiomorphic. This species appears to be the closest living ancestor of the genus. In subgenus Aristea we continue to recognize three sections, sect. Racemosae , sect. Singulares and sect. Aristea. Nesting of subgenus Pseudaristea within section Racemosae of subgenus Aristea is probably an artefact of the analysis and does not receive bootstrap support, and hence we continue to recognize this group of species at subgeneric rank.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 41–68.  相似文献   

10.
Comparisons of the flavonoid patterns in stems and inflorescences between Australasian and South African members of the Restionaceae indicate significant differences with geography. Nine of 14 Australasian species contain gossypetin or a related 8-hydroxyflavonoid and proanthocyanidins are uncommon. By contrast, the 33 South African taxa studied contain common flavonols, flavones and glycoflavones, while proanthocyanidins are present in 29. Two anatomically related South African genera, Chondropetalum and Elegia, contain, in addition, myricetin 3-galactoside, together with the 3-galactosides of the myricetin methyl ethers, larycitrin and syringetin. These results confirm the conclusions derived from anatomy that members of Hypolaena, Leptocarpus and Restio, genera represented in both Australia and South Africa, have the distinctive flavonoids characteristic of their geographic origin rather than of their systematic position. The family as a whole is different in flavonoid pattern from other monocotyledonous families with which it is sometimes associated.  相似文献   

11.
We report the first fossil pollen from South America of the lineage that includes the recently discovered, extremely rare Australian Wollemi Pine, Wollemia nobilis (Araucariaceae). The grains are from the late Paleocene to early middle Eocene Ligorio Márquez Formation of Santa Cruz, Patagonia, Argentina, and are assigned to Dilwynites, the fossil pollen type that closely resembles the pollen of modern Wollemia and some species of its Australasian sister genus, Agathis. Dilwynites was formerly known only from Australia, New Zealand, and East Antarctica. The Patagonian Dilwynites occurs with several taxa of Podocarpaceae and a diverse range of cryptogams and angiosperms, but not Nothofagus. The fossils greatly extend the known geographic range of Dilwynites and provide important new evidence for the Antarctic region as an early Paleogene portal for biotic interchange between Australasia and South America.  相似文献   

12.
In the present paper, a new sect. Leptothece W. T. Wang & Bing Liu wih its only new species, Anemone xiaowutaishanica W. T. Wang & Bing Liu, of the genus Anemone is described and illustrated. In having vertical rhizome, rosulate leaves, 1-flowered cyme, sessile involucre bracts, linear stamen filaments, tricolpate pollen grains with spinulose tectum, and subulate styles, sect. Leptothece is related to sect. Himalayicae (Ulbr.) Juz. From the latter it differs in its 3-parted or 3-sect involucre bracts, 3 carpels per flower, and strongly bilaterally compressed ovary, and with these advanced characters it is remarkably more advanced than sect. Himalayicae, and might be derived from the latter. Anemone xiaowutaishanica with its small distribution area restricted to a valley in the Mt. Xiaowutai, Hebei Province, China is obviously a stenochoric species, and on the basis of its advanced morphological characters it may be regarded as a neoendemic.  相似文献   

13.
Pollen morphology of ten Brazilian species within the South American clade (ca. 20 species) of Symplocos section Barberina (Symplocaceae) was analyzed with scanning electron microscopy to assess their reported androdioecious breeding system. All species exhibited pollen dimorphism. Pollen from male individuals is well developed and 3-colporate, whereas that from morphologically hermaphroditic individuals is malformed, often completely fragmented, lacks cytoplasm, and has no germination pores. Our results suggest that the morphologically hermaphroditic species of S. section Barberina with malformed pollen are cryptically dioecious.  相似文献   

14.
The pollen grains of South American hexaploid representatives of the Mimulus glabratus complex, section Simiolus, and M. bridgesii, a South American species sometimes included in this complex and sometimes in section Paradanthus, were examined by light and scanning electron microscopy. Mimulus bridgesii has (6-) 4–5-zoniaperturate grains nearly identical to those observed in a complex of species in section Paradanthus. South American members of the M. glabratus complex (M. bridgesii excluded) have the irregularly synaperturate, ± spiraperturate pollen typical of section Simiolus (sensu Grant). Treatment of M. bridgesii as a palynologically aberrant member of section Simiolus is not supported by what is known about the evolution of pollen types in Mimulus and the evolution and dispersal of the M. glabratus complex.  相似文献   

15.
16.
Alternative hypotheses in higher-level marsupial systematics have different implications for marsupial origins, character evolution, and biogeography. Resolving the position of the South American monito del monte (Order Microbiotheria) is of particular importance in that alternate hypotheses posit sister-group relationships between microbiotheres and taxa with disparate temporal and geographic distributions: pediomyids; didelphids; dasyuromorphians; diprotodontians; all other australidelphians; and all other marsupials. Among Australasian marsupials, the placement of bandicoots is critical; competing views associate bandicoots with particular Australasian taxa (diprotodontians, dasyuromorphians) or outside of a clade that includes all other Australasian forms and microbiotheres. Affinities of the marsupial mole are also unclear. The mole is placed in its own order (Notoryctemorphia) and sister-group relationships have been postulated between it and each of the other Australasian orders. We investigated relationships among marsupial orders by using a data set that included mitochondrial and nuclear genes. Phylogenetic analyses provide support for the association of microbiotheres with Australasian marsupials and an association of the marsupial mole with dasyuromorphs. Statistical tests reject the association of diprotodontians and bandicoots together as well as the monophyly of Australasian marsupials. The origin of the paraphyletic Australasian marsupial fauna may be accounted for by (i) multiple entries of australidelphians into Australia or (ii) bidirectional dispersal of australidelphians between Antarctica and Australia.  相似文献   

17.
Fourteen native species of Linum are recognized in southern Africa, all of which belong to sect. Linopsis. Four are commonly accepted species; four were described more than a century ago but have not been recognized in recent treatments; six are newly described. Thirteen species are endemic; one ranges as far north as Angola and Tanzania. Among the new species two are heterostylous, the first described for the genus from this region.
The section Linopsis ranges broadly from the Mediterranean region to southern Africa and to both North and South America. The occurrence in the Mediterranean region of species exhibiting such features as heterostyly and chromosome numbers of 2n = 18 or 20, the only diploids known in the section, seems to indicate that in that region are to be found the most primitive species of the section. The close similarity between species of southern Africa and a number of South American and North American species appears to place the southern African species in an intermediate evolutionary position with respect to the Old and New World species of the section.  相似文献   

18.
Abstract Aphis clerodendri Matsumura is newly recorded from Australia and is known from the Northern Territory, on islands in Torres Strait, and in rainforest in northern Queensland and New South Wales. It induces the formation of leaf pseudogalls on native species of Clerodendrum and is commonly attended by ants, which penetrate and may polydomously nest in the galls. Previously known only from eastern Asia, A. clerodendri can now be classified as native to Australia and Australasian in natural distribution. The species is also newly recorded from Papua New Guinea and Vietnam.  相似文献   

19.
总状花序组隶属于凤仙花亚属凤仙花属,以具多花的总状花序、侧生萼片2枚、子房5室、果实为线状圆柱形、种子多数、迈卵形、种皮表面具指状突起等特征区别于该亚属的其他类群。前人对凤仙花花粉形态的研究表明凤仙花属的花粉形态对于属下分类及种间界定具有重要的分类学价值。而对于总状花序组来说,有关花粉形态方面的研究少有报道,为了进一步探讨该组花粉S的形态特征及其分类学意义,该研究应用扫描电镜技术对总状花序组的21种植物的花粉进行了观察。结果表明:总状花序组植物的花粉粒均具4条萌发沟,两侧对称,极面观为矩圆形、长矩圆形或近方形;长赤道面观多为椭圆形至矩圆形,短赤道面观为椭圆形;长、短赤道轴比值多在1.4~2.4范围内;表面具网状纹饰,网眼在花粉粒表面均匀分布或赤道面的网眼较极面观的小,网脊边缘光滑或具波状突起,网眼内具不同密度的颗粒状突起。该组的花粉形态与宏观形态性状相关性较小,但花粉极面观形状、长短赤道轴的比值、网眼的分布、网脊边缘形状、网眼内颗粒物密度等特征具有种水平上的稳定性和特异性,对该组植物种间界定具有重要的意义。  相似文献   

20.
1. Fig trees (Moraceae: Ficus) are keystone species, whose ecosystem function relies on an obligate mutualism with wasps (Chalcidoidea: Agaonidae) that enter fig syconia to pollinate. Each female flower produces one seed (fig female reproductive function), unless it also receives a wasp egg, in which case it supports a wasp. Fig male reproductive function requires both male flowers and pollinator offspring, which are the only vectors of fig pollen. 2. The mutualism is exploited by other wasps that lay eggs but provide no pollination service. Most of these non‐pollinating fig wasps (NPFWs) do not enter syconia, but lay eggs through the wall with long ovipositors. Some are gall‐makers, while others are parasitoids or lethal inquilines of other wasps. 3. Ficus is pan‐tropical and contains >750 fig species. However, NPFW communities vary across fig lineages and continents and their effects on the mutualism may also vary. This provides a series of natural experiments to investigate how the costs to a keystone mutualism vary geographically. 4. We made the first detailed study of the costs of NPFWs in a fig (Ficus obliqua G. Forst) from the endemic Australasian section Malvanthera. In contrast to the communities associated with section Americana in the New World, wasps from the subfamily Sycoryctinae (Chalcidoidea: Pteromalidae) dominated this community. 5. These sycoryctine wasps have a negative impact on pollinator offspring numbers, but not on seed production. Consequently, while the NPFW fauna varies greatly at high taxonomic levels across continents, we show that the consistent main effect of locally dominant exploiters of the mutualism is to reduce fig male reproductive function.  相似文献   

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