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1.
Previous taxonomic assessments of the hydrophytic genus Nuphar Sm. (Nymphaeaceae) have inadequately considered the range of morphological variation existing in the genus. A comprehensive statistical analysis of morphological features among the recognized taxa of Nuphar is presented here, first using 10 fruit characters to delimit the separation of two infrageneric groups of taxa, and secondly using 31 characters to quantify the morphological variation found within sect. Nuphar. Results from combined phenetic analyses provided empirical support for recognition of two infrageneric groups of species in the genus (largely by fruit, stigmatic disk margin, neck, and stigmatic disk size) and for separation of taxa within sect. Nuphar (by leaf size, and fruit disk and neck size). Statistical analyses demonstrate that extensive variation in ranges of character states exists among sect. Nuphar taxa. However, a suite of qualitative and quantitative characters can be used to recognize five species and three subspecies within this predominantly Old World assemblage.  相似文献   

2.
The capitular and floral morphology and anatomy ofBidens L. andCoreopsis L. were studied. All the North American species ofCoreopsis were studied. Selected species ofBidens from North and South America andCoreopsis from South America were included. The results were compared with previous observations on African species ofBidens (incl.Coreopsis). Emphasis was given to character states of the ray florets, paleae, stylearm apices, outer phyllaries, achenes, and pollen grains. Some of the character states are unique features ofCoreopsis, e.g., globular and elongately conical receptacles, deltoid outer phyllaries, truncate and indistinctly 3–5-dentate, 3–4-lobed ray florets, narrowly spathulate paleae, subulate paleae with linear-filiform upper half, hairy and apically 3-cleft paleae, truncate, convex or shallowly conical stylearm apices with the sweeping hairs limited to the area above the stigmatic surfaces and the orbicular to circular achenes. The cylindric setaceous pappus bristles so commonly encountered inBidens are unknown inCoreopsis. The pappus bristles inCoreopsis are paleaceous but similar, though thicker ones are also found in African species ofBidens (incl.Coreopsis) with winged achenes. Twin-celled hairs (setulae) with differing degrees of wall thickness are found on the achenes ofCoreopsis sect.Pseudoagarista (Mexico and South America),Coreopsis sect.Pugiopappus (California), AfricanBidens with winged achenes (e.g.,B. prestinaria, B. macroptera) and some North AmericanBidens (e.g.,B. aristosa). Similar sclerotic parenchyma make up the achenial wings of species in both genera. These may be interpreted as homologous structures, indicating the underlying similarity of these taxa and their derivation from a common ancestral stock.  相似文献   

3.
Dendrobium sect. Dendrocoryne is a difficult taxonomic group of allied species and species complexes, occurring on the eastern Australian coastline, Lord Howe Island and New Caledonia. Significant morphological characters were assessed from all key areas of the distribution range. Patterns of variation between species, varieties and hybrids were investigated by principal coordinate analysis. The analyses affirm 12 species in the sect. Dendrocoryne described by Schlechter (1912, 1982) and Dockrill (1969, 1992), including a cluster of small statured D. gracilicaule, D. adae, D. fleckeri, and D. finniganense, and three variable species complexes – D. speciosum, D. kingianum and D. tetragonum. Recently described D. finniganense and D. callitrophilum are interpreted as members of the section. Phylogenetic relationships are presented based on parsimony analysis of 31 morphological characters. Analyses do not support proposals to recognize new genera for D. tetragonum, D. callitrophilum and D. aemulum, or to create new species within D. tetragonum, D. jonesii, D. speciosum and D. kingianum. The phylogeny indicates that rainforest taxa are earlier lineages and xerophytic taxa are more derived.  相似文献   

4.
Lepidaploa belongs to tribe Vernonieae, one of the most complex tribes of Asteraceae, and the relationships within Lepidaploa and among related genera are poorly understood. Microcharacters may be of taxonomic value and may be used in the identification of taxa at different ranks. To evaluate the reliability of microcharacters as taxonomic markers in this group, we analysed the micromorphology of phyllaries, florets and cypselae in detail in 23 species of Lepidaploa .The species were studied using stereo, light, and scanning electron microscopy. Eight trichome types (eglandular and glandular) were observed on phyllaries, florets and cypselae, in addition to crystals, idioblasts and other microstructures. The results demonstrates that the ocurrence of different combinations of trichome types and crystals, presence of a stylar basal node, idioblasts and glandular apical anther appendages are highly useful to differentiate between related species of Lepidaploa and a diagnostic key using these characters is presented. However, these characters are not of much use to distinguish between closely related genera of Vernonieae since most characters appear homeoplasic and are found in representatives of different genera.  相似文献   

5.
Ipheion, as recognized by Guaglianone (Darwiniana 17:159–242, 1972), is a small genus of the family Amaryllidaceae, subfamily Allioideae, tribe Gilliesieae endemic to South America. Since 1800, the species of Ipheion were treated under Beauverdia, Brodiaea, Milla, Nothoscordum, Tristagma or Triteleia. Nowadays, some species of Ipheion are treated as Tristagma and some other under Nothoscordum. In this paper, we analyzed the morphological variation among species of Ipheion and related genera using a numerical taxonomic approach based on overall similarity, to investigate the intergeneric and infrageneric variations to the circumscribed groups. Based on 141 operational taxonomic units and 51 morphological characters, multivariate analyses were performed. Results showed that Ipheion separated into two groups according to Guaglianone’s sectional treatment: Ipheion sect. Ipheion is morphologically more similar to the studied species of Tristagma, while I. sect. Hirtellum can be separated from Nothoscordum/Zoellnerallium and from Tristagma and allies. These a priori groupings were tested using discriminant and univariate analyses. Diagnostic characters were selected to differentiate groups. Previous taxonomic treatments are discussed and results are also evaluated using additional karyological and geographical data.  相似文献   

6.
Geometric and traditional morphometric approaches are tested to describe and reveal taxonomic characters and character states in variation of shape and size of idiosoma morphology in the Arrenuridae. Patterns of variation of idiosoma and glandularia features of males from 11 Mexican species of Arrenurus (Megaluracarus) and two species of subgenus Dadayella were explored with five landmark configurations and three sets of interlandmark distances. Separate principal component analyses (PCA) and canonical variate analyses (CVA) were performed for each data set. The eight multivariate analyses of variance among 13 a priori groups (species) detected significantly different morphometric variants, which were interpreted as different taxonomic character states. Patterns of character state similarity among species were examined with unweighted‐pair grouping method using averages (UPGMA) cluster analyses on Mahalanobis distances. Analyses of five landmark configurations revealed important taxonomical variation in the anterior idiosoma outline (10 character states), the outline of the posterior region or cauda (13 states), the distribution of postocularia, and the second and third pairs of dorsoglandularia (nine states), the fourth pair of dorsoglandularia (three states), and ventroglandularia on the posterior side of idiosoma (nine character states). Multivariate analyses of three sets of distance measurements also resulted in the detection of potential taxonomic characters related to idiosoma size (12 character states), postocularia and dorsoglandularia (13 states), and ventroglandularia (nine character states). Morphometric analyses of distances and shapes provide a formal basis for the interpretation of taxonomic characters, and for the discovery of character states. These characters should be investigated further in a wider sample of species for the phylogenetic systematics of these water mites. In the meantime, idiosoma regions and structures were tested for congruence in a phylogenetic analysis, and were proposed as homologous among the species sampled.  相似文献   

7.
Fresh leaves of 150 individuals from 15 populations representing five putative species of Stachys sect. Fragilicaulis, subsect. Fragiles distributed in the Zagros mountains in western Iran were analyzed for isoenzyme variation. Four enzyme systems (peroxidase, esterase, superoxide dismutase and ascorbate peroxidase) have been studied and a total of 32 bands representing seven putative loci have been analyzed by UPGMA using the Euclidean distances. UPGMA analysis resulted in the recognition of three distinct clusters among the considered populations. The average value of Shannon diversity index (H′) estimated for each population ranged from 0.05 to 2.17. The mean number of bands per isoenzyme ranges from 1.60 to 2.50. The value of Euclidean distance ranges from 0.85 to 3.79. The analysis of isoenzyme variation patterns suggests recognizing following species in Stachys sect. Fragilicaulis subsect. Fragiles: Stachys benthamiana (including Stachys megalodonta), Stachys kurdica (including Stachys ballotiformis) and Stachys asterocalyx. These data also suggest paying more attention to geographical distribution of taxa in Stachys for their taxonomic delimitation. This study provides another strong support for application of electrophoretic analysis of isoenzymes in taxonomy at species level.  相似文献   

8.
Fifteen cranial measurements were taken from wild caught specimens ofAlouatta seniculus seniculus, A. s. stramineus andA. s. macconnelli. A morphological analysis showed sex dimorphism in these three groups. A multivariate analysis discriminated among these taxa; males being more clearly discriminated than females. Our data showed that these taxa can be separated on the basis of quantitative cranial traits, biogeographic distribution, karyological differences, and biochemical characters. We therefore propose a new taxonomic arrangement, changing their taxonomic status to the species level (Alouatta seniculus, A. macconnelli, andA. stramineus).  相似文献   

9.
The DNA ploidy level of 673 accessions belonging to 238 species of Hieracium have been analyzed by flow cytometry. 222 of the species were of Scandinavian origin as members of the exclusively apomictic H. sectt. Bifida, Hieracium, Oreadea, Tridentata and Vulgata. For the overwhelming majority of the species, the ploidy level (or chromosme number) has never been investigated before. Approximately 50% of the Scandinavian species, previously believed to be exclusively triploid, were found to be tetraploid. In addition, two pentaploid samples, viz. H. intermarginatum Johanss. & Sam. from Sweden and H. cf. plumbeum Blytt & Fr. from Germany, were found. Although two or more accessions from geographically remote sites were analyzed for approximately 50% of the Scandinavian species, only 2 (<2%) taxonomically undisputed species were found to consist of plants with more than one ploidy level. An intriguing pattern was revealed among Scandinavian members of H. sectt. Bifida and Vulgata when ploidy level and morphometric variation was compared, viz. the most typical or extreme representatives of these sections were found to be exclusively triploid whereas tetraploids dominate among species with intermediate morphology and among species morphologically intermediate between these sections and H. sect. Hieracium. This pattern may indicate that the tetraploids, which tend to have mainly northern distributions, have originated as the result of rare sexual hybridizations between triploid members of different sections, plausibly during or after the northward migration of the parental linages after the last glaciation. The results are believed to be highly relevant for understanding the processes of evolution and speciation within the predominantly apomictic genus Hieracium, but it is emphazised that additional data from e.g. molecular markers and pollen viability analysis are needed before any trustworthy conclusions can be made as far as evolutionary processes are concerned.  相似文献   

10.
In this study we present a survey on vegetative anatomy in species of Actinocephalus, Blastocaulon, Eriocaulon, Leiothrix, Paepalanthus, Philodice, Syngonanthus, and Tonina (Eriocaulaceae). Multivariate analyses were used to correlate anatomical characters to taxa and the habitats where the species occur. Root and stem anatomical characters seem to be more affected by environmental factors where these species occur, and seem of little value for delimiting major taxonomic groups within the family. Other characters in the leaves, such as epidermis with thickened wall cells, compartmented substomatal chambers, mesophyll with hypodermis, compact chlorenchyma, collenchymatous bundle sheath extensions, and numerous vascular bundles, were shown to be important for defining species clusters in Leiothrix, Syngonanthus, and Paepalanthus subg. Platycaulon. Similarly, loosely aggregated chlorenchyma caused Blastocaulon, Eriocaulon, Philodice, Syngonanthus sect. Carpocephalus, S. sect. Syngonanthus, and Tonina, genera from humid environments, to cluster. Scape characters appear to be more informative in discriminating groups. This situation probably reflects lower selection pressures determining anatomical characters of this organ.  相似文献   

11.
黄姗  杨韩  苏春  常朝阳 《西北植物学报》2018,38(9):1646-1658
采用体视显微镜和扫描电子显微镜,对中国产黄耆属糙叶组34种植物的叶表皮毛状体的形态特征及其分布进行了观察,以探讨中国黄耆属糙叶组物种表皮毛微观形态的变异式样及其分类学意义,为糙叶组物种的分类鉴定提供依据。结果表明:除乳白花黄耆(A. galactites)仅在叶下表面被毛外,其余种类上下表皮均有毛,且毛的分布、形态、长度和臂比在不同种类间存在差异。叶表皮毛为伏贴或开展的中空管状毛,伏贴毛着生部位基部膨大,整体形态从中部向两端由粗逐渐变细,开展的毛大部分为细长的丝状或线状,光滑或具条纹状纹饰,上面分布有乳突。研究认为,叶表皮表面伏贴、短而平直、其上光滑具密集乳突、臂比值小、整体宽扁的毛是祖先特征;而叶表皮表面向上开展、长而密集、外形呈丝状或线形、其上具条纹状纹饰、乳突稀疏、臂比值大的毛是进化特征。  相似文献   

12.
13.
Principal component and canonical variate analyses were used to analyse the variation of 34 morphological characters measured in 98 accessions ofTulipa subg.Tulipa, formerly known as sect.Leiostemones. In addition 43 accessions were analysed cytogenetically by means of C-banding methods. Based on the encountered variation and on geographical distribution data 30 species in five sections were recognized, of which the synonymy is stated. Seven new series in two different sections have been designated.  相似文献   

14.
Morphological and RAPD markers were used to assess the relationships among nodulating and non-nodulating species of AfricanAcacia. Non-nodulating species of AfricanAcacia are only found within subg.Aculeiferum sect.Monacanthea. African species of sect.Monacanthea examined were found to form a group distinct from the other African species examined on a morphological and molecular basis. All lack the ability to nodulate, suggesting that non-nodulation may be used as a taxonomic tool. The species of sect.Aculeiferum were separated by RAPD and morphological analysis into two groups depending on whether they were armed with prickles in pairs and/or prickles in threes, or solitary. A third group of species was identified within sect.Acacia: further subdivision of this group was achieved into subsectt.Pluriseriae andUniseriae. The position ofA. albida relative to other AfricanAcacia species was found to be distinct but not totally independent of the genus. The partitioning and distribution of the genetic variability within the genus is further elucidated by the RAPD analysis of populations ofAcacia species. A population analysis ofA. polyacantha demonstrated geographical and site-specific variation.  相似文献   

15.
燕麦属颖果微形态特征及其分类学意义   总被引:1,自引:0,他引:1  
为探讨燕麦属颖果微形态特征的分类学意义,采用体视显微镜和扫描电子显微镜观察燕麦属27种颖果的微形态特征,结合分子系统发育证据分析其分类学意义。燕麦属颖果有纺锤形、倒披针形、椭圆形3种形状,条纹、棱纹、网纹3种纹饰。燕麦属颖果形状、纹饰和花柱基宿存模式具有有限的属下分类学意义,颖果大小和表面大毛密度具有种间鉴定价值,而颖果腹面形态、压扁方式、胚比不具有种间鉴定价值。大穗燕麦(Avena macrostachya Balansa ex Coss.Durieu)颖果纺锤形,条纹纹饰,隶属于燕麦属颖果微形态特征的变异范围。大粒裸燕麦(A.nuda L.)与普通栽培燕麦(A.sativa L.)颖果大小、形状及纹饰特征的差异支持将大粒裸燕麦作为独立种处理。燕麦属颖果大小、表面大毛密度、胚比变异幅度大,推测与分布区广幅的气候变异相适应,凹腹面颖果体积相对缩减,有利于颖果快速发育、成熟,推测与燕麦属植物在温带、寒带分布区适生期较短相适应。  相似文献   

16.
In the present study, seeds of 13 Oxytropis DC. species (including two latest synonyms) classified in subg. Oxytropis (sect. Dolichocarpon, sect. Chrysantha and sect. Eumorpha), subg. Euoxytropis (sect. Orobia) and subg. Phacoxytropis (sect. Protoxytropis, sect. Janthina and sect. Mesogaea) from Turkey were examined using light and scanning electron microscopy to evaluate the taxonomic relevance of macro- and micro-morphological seed characters. As a result of the study, species-specific characters have been determined. Seeds exhibit variation in size, shape, surface sculpturing pattern, hilum position and weight. Seeds ranged from 1.61 to 4.04 mm in length and from 1.02 to 2.56 mm in width. Five different seed shapes were recognised, as prolonged semielliptic, reniform, prolonged reniform, quadratic and cardiform, with a length to width ratio ranging from 1.02 ± 0.08 to 1.75 ± 0.27. Rugulate, rugulate–reticulate and lophate sculpturing patterns were observed in the studied species. According to the results, seed characters, such as the size (length, width and the length/width ratio), the shape, the surface sculpturing and the weight appear to have low taxonomic value in distinguishing subgenera, sections and species.  相似文献   

17.
18.
Two new species of Centaurea L. sect. Cynaroides Boiss. ex Walp. (Asteraceae), C. shahuensis Ranjbar and Negaresh and C. ravansarensis Ranjbar and Negaresh are described and illustrated from Kermanshah Province, west Iran. They are closely related to C. regia Boiss. subsp. regia. However, C. shahuensis differs from it by median stem leaves broadly oblanceolate or subpandurate, phyllaries densely lanate‐tomentose, appendages small, concealing a minor part of phyllaries, and also median appendage margin entire sometimes with 1–2 cilia, 1.2–3.0 mm long on each side. Centaurea ravansarensis is distinguished by upper stem leaves loosely arachnoid, phyllaries loosely floccose‐tomentose, inner appendages deep brown to blackish, and spine 4.5–6.0 mm long. Habitat, conservation status and the geographical distribution of the new species are given.  相似文献   

19.
We have examined morphological and chromosomal variation inFallopia sect.Reynoutria in Korea to clarify their taxonomic identities and to determine whether their morphological variability is associated with ploidy levels. Principal components analysis (PCA) of individuals from 21 populations, using major distinguishing characters, revealed the presence of four major entiries of sect.Reynoutria in Korea; these includeF. sachalinensis, F. japonica var.japonica, F. forbesii, and the Nonsan population consisting of presumed hybrids. Based on morphology, it is hypothesized that the Nonsan population was probably derived from multiple hybridization events involving the three named taxa. The results also indicate thatF. forbesii is distinct fromF. japonica var.japonica. Polyploidy is more prevalent in sect.Reynoutria than has been previously recognized.Fallopia sachalinensis in Korea occurs as dodecaploids with 2n=132; our count is the first dodecaploid count for the species, and represents the highest chromosome number known in the genus.Fallopia japonica var.japonica occurs as tetraploids (2n=44), hexaploids (2n=66), and octoploids (2n=88), whileF. forbesii occurs as hexaploids (2n=66) and octoploids (2n=88); our counts appear to be the first reported chromosome numbers forF. forbesii. Morphological analysis indicates that there is no apparent correlation between the ploidy levels in these taxa and the morphological characters that we have considered in this study except that the tetraploids ofF. japonica var.japonica tend to have somewhat thicker leaves.  相似文献   

20.
Asplenium sect.Hymenasplenium is a well-defined group in Aspleniaceae, distinguished by several morphological and cytological characters. However, interspecific relationships in the section were not clear. In this paper, we report the phylogenetic relationships of 9 Neotropical species of sect.Hymenasplenium determined by chloroplast DNA restriction site variation analyses. From the obtained phylogenetic tree, two major clades: one withA. obtusifolium, A. riparium, A. volubile andA. repandulum and another withA. delitescens, A. ortegae, A. purpurascens, A. laetum andA. hoffmannii were recognized.Asplenium delitescens was shown to have a polyphyletic origin. It was also shown that the epiphytic habit evolved only once in the New World species of sect.Hymenasplenium.  相似文献   

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