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1.
The African genus Welwitschiella has traditionally been placed in tribe Heliantheae. Our phylogenetic analysis of chloroplast DNA ndhF sequence data, however, reveals that it is part of tribe Astereae. In order to assess the relationships of this genus within the tribe, we produced a phylogeny based on ITS (nrDNA) sequence data of a sample including Amellus, African Conyza, Chrysocoma, Felicia spp., Mairia, Poeciliopsis, Printzia, Welwitschiella and Zyrphelis. Both parsimony and Bayesian analyses were done. The Bayesian analysis showed that African genera form a basal grade in tribe Astereae along with the Chinese Nannoglottis and South American and New Zealand genera, with Printzia being the earliest diverging member of the tribe. Mairia occupies an isolated position. Amellus, Chrysocoma, Felicia, Poecilolepis and Zyrphelis belong to subtribe Homochrominae, a South African radiation that also includes the St Helena endemics Commidendron and Melanodendron. Pteronia appears isolated, though it might be close to the Homochrominae. Welwitschiella is placed in the latest diverging African clade, subtribe Grangeinae, which also includes Grangea, Psiadia, Nidorella, and the African Conyza species except C. gouani. This subtribe is sister to the Eurasiatic subtribe Bellidinae, and together they are sister to the Astereae crown lineages of Australasia-Asia and South and North America.  相似文献   

2.
Cyathocline, a small genus, has been treated as a member of subtribe Grangeinae of tribe Astereae (Asteraceae), but has been neglected in molecular phylogenetic analyses of Astereae. Plastid trnL-F and nuclear ribosomal DNA ITS sequences were used to carry out phylogenetic analyses of Cyathocline (represented by C. purpurea) through maximum parsimony and Bayesian analyses. In addition, its karyotype, morphology and micromorphology were also investigated. The results show that in our three phylogenetic trees, C. purpurea is deeply nested within the Blumea clade and/or the Inulinae clade, and is closest to Blumea balsamifera (Inuleae, Inulinae). C. purpurea is similar to Blumea in chromosome size bimodality and to Inulinae in one single large oxalate crystal within each cell of the cypsela epidermis, which, together with molecular evidences, suggests strongly that Cyathocline should be transferred from Astereae to Inuleae subtribe Inulinae. Although C. purpurea has many anomalous features, its most characters still are within a wide range of morphological variations of Blumea. DNA data and the karyotypic character support to merge C. purpurea into Blumea. As a result, the new combination Blumea purpurea (O. Kuntze) W.P. Li was made.  相似文献   

3.
Chiliotrichiopsis peruviana Nesom, H. Rob. & Granda, a new species from Dept. Ayacucho in southwestern Peru, is described and illustrated. It is the only rayless species of the genus, now expanded to four species, and the only one that occurs outside of Argentina.Chiliotrichiopsis is one of six shrubby South American genera of Astereae (subtribe Hinterhuberinae) with paleate receptacles. Observations on morphology and a key to these genera provide perspective for the generic placement of the new species.  相似文献   

4.
Forty-five sequences from members of all genera of Asteraceae indigenous to New Zealand and 50 published sequences representing the tribal diversity in the family were analyzed to assess the utility of ITS sequences to resolve phylogenetic relationships. Previous studies using chloroplast DNA sequences and morphology provided support for several clades in the Asteraceae, yet the relationships among some of these were uncertain. The results from ITS analysis were largely consistent with these earlier studies. The New Zealand species are included in at least six clades, most of these corresponding to recognized tribes. Our results have also clarified the tribal affinities of a few anomalous genera. Haastia, previously aligned with the Gnaphalieae or the Astereae, is nested in the Senecioneae. Centipeda, previously included in the Astereae or Anthemideae, emerges near the Heliantheae. The relationships of Abrotanella remain unresolved. Received August 8, 2001 Accepted November 6, 2001  相似文献   

5.
报道了甘肃省菊科植物的3个分布新记录属,母菊属(Matricaria),联毛紫菀属(Symphyotrichum)和艾纳香属(Blumea),以及3个甘肃省分布新记录种,同花母菊[Matricaria matricarioides(Lessing)Porter ex Britton],钻形紫菀[Symphyotrichum subulatum(Michaux)G.L.Nesom]和柔毛艾纳香[Blumea axillaris(Lamarck)Candolle]。  相似文献   

6.
7.
Species delimitation through which infers species boundaries is emerging as a major work in modern systematics. Hop‐hornbeam species in Ostrya (Betulaceae) are well known for their hard and heavy woods. Five species were described in China and their interspecific delimitations remain unclear. In this study, we firstly explored their distributions in all recorded field sites distributed in China. We then selected 110 samples from 22 natural populations of five species from this genus and one type specimen of O. yunnanensis, for molecular barcoding analyses. We sequenced four chloroplast (cp) DNA fragments (trnH–psbA, trnL–trnF, rps16, and trnG) and the nuclear internal transcribed spacer (ITS) region for all samples. Sequence variations of Ostrya from four cpDNA fragments identified three groups that showed no correspondence to any morphological delimitation because of the incomplete lineage sorting and/or possible interspecific introgression in the history. However, phylogenetic analyses of ITS sequence variations discerned four species, O. japonica, O. rehderiana, O. trichocarpa, and O. multinervis while O. yunnanensis nested within O. multinervis. Morphological clustering also discerned four species and showed the complete consistency with molecular evidence. Moreover, our phylogenetic analyses‐based ITS sequence variations suggested that O. trichocarpa comprised an isolated lineage different from the other Eurasian ones. Based on these results, hop‐hornbeams in China should be treated as four separate species. Our results further highlight the importance of ITS sequence variations in delimitating and discerning the closely related species in plants.  相似文献   

8.
Balanus glandula, an east Pacific acorn barnacle from rocky shores, was introduced to Mar del Plata, Argentina more than 40 years ago and has spread over 17 latitudinal degrees southward. Here we report the first record of this species living in a soft-bottom environment colonizing the salt marsh plant species Limonium brasiliense, Spartina densiflora, S. alterniflora and Sarcocornia perennis. In addition, we describe the size frequency distribution, density and spatial distribution of the barnacles colonizing the different plant species. The size frequency distribution of Balanus showed a bimodal pattern in all plants. Barnacles were mostly large in S. densiflora, but small in S. alterniflora, with more balanced distributions of small and large barnacles on S. perennis and L. brasiliense. The highest density of barnacles was observed on S. perennis (x = 35.8 ind/cm2, SD = 40.5) and S. alterniflora (x = 33.8 ind/cm2, SD = 23), while the lowest on L. brasiliense (x = 1.5 ind/cm2, SD = 1.18) and S. densiflora (x = 0.17 ind/cm2, SD = 0.09). More than 90% of the barnacles on any given plant were found living. While barnacles colonized only the first few centimeters above the soil surface level in S. alterniflora and L. brasiliense, they reached their highest point on S. perennis. The finding of a rocky shore species successfully colonizing soft-bottom marshes within an invaded region brings new perspectives to discussions in biological invasion ecology, and raises additional considerations for coastal environmental management.  相似文献   

9.
Phylogenetic relationships within Euphorbiinae were inferred from our analysis of the 3′; end of the chloroplast gene ndhF. A sampling of that subtribe covered 88 species; 3 closely related species from the subtribes Anthosteminae and Neoguillauminiinae and the tiribe Hippomaneae were included as outgroups. A phylogenetic assessment was carried out using the parsimony approach. The relationships revealed via these ndhF data supported the monophyly of subg.Esula, subg.Chamaesyce, subg.Euphorbia, and subg.Lacanthis. However, the polyphyly of subg.Agaloma, subg.Lyciopsis, and subg.Eremophyton also was strongly suggested. The African succulent Euphorbiinae can be divided into primarily two independent groups: 1) spiny succulents, which form a strongly supported clade with three subclades (subg.Euphorbia, subg.Lacanthis, andMonadenium+Synadenium); and 2) non-spiny succulents, which consist of sect.Meleuphorbia, sect.Medusae, sect.Anthacantha, sect.Trichadenia, sect.Pseudeuphorbium, sect.Treisia, and sect.Pseudacalypha. In the ndhF tree, the subg.Esula clade is placed as a sister to the rest of the Euphorbiinae. Thus, the origin of theEuphorbia s.I. should be sought within the herbaceous species of subg.Esula. The core North American endemicEuphorbia groups --Agaloma, Chamaesyce, andPoinsettia — are monophyletic and independent of the South American subg.Agaloma. Instead, they are derived from the AfricanEuphorbia subg.Lyciopsis andEremophyton. The Eurasian subg.Esula clade forms two subclades, which are concordant to sect.Esula and sect.Tithymalus.  相似文献   

10.
11.
Chromosome number determinations from 118 populations of eight species of the aster genus Virgulus are reported for the first time. Based on these counts and literature reports the geographic distributions of diploids and tetraploids in V. concolor, V. novae-angliae, V. oblongifolius, and V. patens have been determined. In the first three species, diploids were widely distributed, while tetraploids were more restricted. In V. patens, diploids were restricted to the southwestern portion of the species’ range, while tetraploids were found throughout the range. Both V. adnatus and V. walteri were found only at the tetraploid level throughout their ranges. Two other species with restricted distributions were consistently found to be high level polyploids: V. georgianus with 2n = 50, V. grandiflorus with 2n = 60. The following new combinations are listed: Virgulus georgianus (Alexander ex Small) Semple; Virgulus subsect. Brachyphylli (Torr. & Gray) Semple; and Virgulus sect. Polyliguli (Semple & Brouillet) Semple.  相似文献   

12.
The phylogenetic relationships of the Chinese species Serratula forrestii and S. chinensis within the subtribe Centaureinae (Asteraceae – Cardueae) were investigated based on nuclear ribosomal DNA external and internal transcribed spacer sequences. Results indicated that Serratula s. l. is clearly polyphyletic, none of the two species showing close affinities to either Serratula s. str. or Klasea, a genus traditionally included in Serratula. Serratula forrestii has a basal position within the subtribe and has retained most plesiomorphic character states. Serratula chinensis is related to the genera of the Rhaponticum group. Its chromosome number was determined as 2n = 26, and the relationship between this species and the Rhapon-ticum group is discussed from a morphological and karyological point of view.  相似文献   

13.
During the period from 2010 to 2013 preharvest symptoms were detected on different cultivars of sweet orange in six orchards in Catania, Siracusa and Enna provinces, Southern Italy. A total of 56 monosporic fungal isolates were obtained, and among these, 44 were identified as Colletotrichum gloeosporioides and 12 as Ckarstii through morphological and molecular analysis. PCR with primers ITS1 and ITS4, primers TubGF1 and TubGR specific for β‐tubulin gene, primers GDF‐GDR, specific for Glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) gene, were used to confirm the identification of Colletotrichum isolates from citrus. The ITS1‐5.8S‐ITS2 region, a portion of approximately 500 bp of β‐tubulin gene and a fragment of 220 bp of GAPDH gene of the isolates were sequenced and analysed with the BLASTn program. Koch's postulates were fulfilled by pathogenicity tests carried out on fruit of ‘Tarocco Scirè’ and ‘Tarocco Nucellare’ with representative isolates of Cgloeosporioides and Ckarstii. Field surveys and pathogenicity tests revealed significant differences in fruit susceptibility between ‘Tarocco Scirè’ and ‘Tarocco Nucellare’ and in virulence between the fungal species. To our knowledge, this is the first report on the emergence of Colletotrichum spp. causing anthracnose in preharvest conditions.  相似文献   

14.
Solanum sect. Petota (tuber-bearing wild and cultivated potatoes) are a group of approximately 190 wild species distributed throughout the Americas from the southwestern United States south to Argentina, Chile, and Uruguay. Solanum series Conicibaccata are a group of approximately 40 species within sect. Petota, distributed from central Mexico to central Bolivia, composed of diploids (2n = 2x = 24), tetraploids (2n = 4x = 48) and hexaploids (2n = 6x = 64); the polyploids are thought to be polysomic polyploids. This study initially was designed to address species boundaries of the four Mexican and Central American species of series Conicibaccata with AFLP data with the addition of first germplasm collections of one of these four species, Solanum woodsonii, as a follow-up to prior morphological, chloroplast DNA, and RAPD studies; and additional species of series Conicibaccata from South America. AFLP data from 12 primer combinations (1722 polymorphic bands) are unable to distinguish polyploid species long thought to be distinct. The data suggest a complex reticulate history of the tetraploids or the need for a broad downward reevaluation of the number of species in series Conicibaccata, a trend seen in other series of sect. Petota. Separately, through flow cytometry, we report the first ploidy level of S. woodsonii, as tetraploid (2n = 48). The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.  相似文献   

15.
Prem P. Jauhar 《Genetica》1968,39(1):360-370
Meiosis in the interspecific hybrid betweenPennisetum typhoides (2n=14; genomeAA) andP. purpureum (2n=28; genomesA′A′BB) has been studied with particular reference to allosyndetic and autosyndetic pairing of chromosomes. Although up to nine bivalents occurred in the hybrid, never more than five were observed to be (heteromorphic)AA′ bivalents (range 1–5). It has been concluded thatA andA′ genomes are onlypartially homologous. It has further been inferred that the two genomes are evolutionarily related and could have arisen from a common progenitor withx=5 chromosomes or from related species withx=5 chromosomes. Autosyndetic pairing of chromosomes within thetyphoides complement (A genome) and within theA′ genome ofpurpureum have been reported here for the first time. Intra-haploid pairing to a probable maximum of two bivalents within each of the three genomes of the hybrid, viz.,A, A′ andB, further suggestsx=5 as the phyletically basic number in the genusPennisetum. It has been inferred thatx=7 is a secondarily basic number, having been derived fromx=5. The occurrence of a species withn=5 inPennisetum, viz.,P. ramosum, substantiates this view. Further support in favour of this conclusion comes from the secondary association of bivalents in dipoidP. typhoides. Thus, the apparently diploid species,Pennisetum typhoides with2n=14 chromosomes is considered to be a “secondary diploid” having a secondarily balanced number ofx=7. On the basis of the results obtained by the author is conjunction with the available evidence from the literature, it is suggested thatx=5 may be the original basic number for the entire grass family and seven, the most preponderant number in it, and other higher numbers derived from it subsequently during the course of evolution.  相似文献   

16.
The goal of this study was to review the impact of DNA sequence analyses on our understanding of Cariceae phylogeny, classification and evolution. To explore character evolution, 105 taxa from four different studies were included in an nrDNA ITS + ETS 1f analysis of all recognized genera (Carex, Cymophyllus, Kobresia, Schoenoxiphium, Uncinia) and Carex subgenera (Carex, Psyllophora, Vignea, Vigneastra). As in previous analyses, four major Cariceae clades were recovered: (1) a “Core Carex Clade” (subg. Carex, Vigneastra, Psyllophora p.p); (2) A “Vignea Clade” (subg. Vignea, Psyllophora p.p.); (3) a “Schoenoxiphium Clade” (Schoenoxiphium, subg. Psyllophora p.p.), and (4) a “Core Unispicate Clade” (Uncinia, Kobresia, subg. Psyllophora p.p.). All studies provide strong support (86–100% BS) for the Core Carex and Vignea Clades, but only weak to moderate support (<50%–78% BS) for the Core Unispicate and Schoenoxiphium Clades. The relationships of these groups are unresolved. Studies suggest that Carex is either paraphyletic with respect to all Cariceae genera or to all genera except Schoenoxiphium. Kobresia is a grade, but Uncinia and possibly Schoenoxiphium are monophyletic. The monotypic Cymophyllus is indistinct from Carex subg. Psyllophora species. Character analyses indicate that inflorescence proliferation and reduction have occurred in all major clades, and that the Cariceae’s unisexual flowers have evolved from perfect flowers. The ancestor to Cariceae possessed a multispicate inflorescence with cladoprophylls and female spikelets with tristigmatic gynoecia and closed utricles. This morphology is most similar to extant Carex subg. Carex species, which contradicts the nearly unanimous assumption that the highly compound inflorescences of Schoenoxiphium are primitive. Since taxonomic sampling and statistical support for phylogenies have generally been poor, we advocate the temporary maintenance of the four traditional Carex subgenera with androgynous unispicate species placed within subg. Psyllophora and dioecious and gynaecandrous unispicate species distributed amongst subgenera Carex and Vignea. A collective effort focused on developing new nuclear markers, on increasing taxonomic and geographic sampling, and on studying development within the context of phylogeny, is needed to develop a phylogenetic classification of Cariceae.  相似文献   

17.
Nymphaea, an aquatic perennial herb with exceptionally beautiful flowers and floating leaves, is well represented globally. Out of ten species reported from India, the internal transcribed spacers (ITS) region of nrDNA was investigated in seven species of Nymphaea viz. N. alba var. rubra, N. caerulea, N. × marliacea, N. nouchali, N. pubescens, N. rubra and N. tetragona. Barring N. pubescens, whereby double peaks detected in the sequencing chromatograms may be due to random mutations occurring in some of the ITS paralogues, the additional signals detected for N. alba var. rubra and N. rubra are probably influenced by recent hybridization and introgression. Our study on sequence characteristics of ITS 1 and ITS 2 revealed high G + C content (ITS 1, 45.5–48.4%; ITS 2, 50.2–51.5%) and sequence divergence. Percentage of sequence divergence based on substitution and substitution plus indels is 44.15 and 57.19, respectively, for the ITS 1; 29.74 and 47.96% were recorded for the ITS 2. Although highly variable, conserved motifs within the ITS 1 and ITS 2 region of Nymphaea were identified and are found to be common throughout the order Nymphaeales. Sequence analysis of the ITS 1 and ITS 2 failed to detect any variation between two morphotypes of N. nouchali, namely N. nouchali JD 06 and N. nouchali JD 07, differing in flower color and found at the same geographical location. However, on comparison with another specimen of N. nouchali found at a different location, they showed considerable variation in nucleotide composition. Complemented by sequence data retrieved from GenBank, phylogenetic tree reconstruction of the genus Nymphaea based on neighbor-joining, maximum parsimony, maximum likelihood and Bayesian inference methods is presented and discussed.  相似文献   

18.
Mitotic chromosome numbers of 32 populations belonging to 23 species of the genus Lessingianthus H.Rob. (Vernonieae, Asteraceae) were determined. The chromosome number of all examined plants was found to be based on x = 16. The numbers observed varied from 2n = 32 to 2n = 176. The results include the first report of the chromosome number for 11 species: L. lanatus (2n = 32), L. varroniifolius (2n = 32), L. cataractarum (2n = 64), L. intermedius (2n = 64), L. argenteus (2n = 96), L. centauropsideus (2n = 96), L. profusus (2n = 96), Lessingianthus sp. nov. 1 (2n = 96), Lessingianthus sp. nov. 2 (2n = 128), L. robustus (2n = 160), and L. macrocephalus (2n = 176). New chromosome numbers were found in the four other species: L. rubricaulis, L. laniferus, and L. sellowii were tetraploid with 2n = 64, while L. oxyodontus was hexaploid with 2n = 96. B chromosomes were observed in L. coriaceus and L. varroniifolius. Lessingianthus macrocephalus (2n = 11x = 176) is reported as the first case of an odd polyploid and the higher chromosome number of Lessingianthus. The significance of the results is discussed in relation to chromosomal data available for the genus.  相似文献   

19.
Fossil pollen grains with morphological features unique in the subtribe Nassauviinae (tribe Mutisieae, Asteraceae) occur in Miocene marine deposits of eastern Patagonia, southern South America. A new morphogenus and two morphospecies are proposed to assemble fossil pollen grains characterized by having a complex bilayered exine structure with delicate columellae, separated by an internal tectum. Subprolate specimens with Trixis exine type (ectosexine thinner than endosexine, straight internal tectum) are referred to Huanilipollis cabrerae. This species is similar to pollen of recent Holocheilus, Jungia, and Proustia. Suboblate specimens with Oxyphyllum exine type (ectosexine and endosexine equally thick, zigzag internal tectum) are referred to Huanilipollis criscii. This species is similar to pollen of recent Triptilion. The spore/pollen sequences in which Nassauviinae pollen types occur suggest a wide range of vegetation types varying from forest dominated during the Early Miocene (Chenque Formation) to virtually xerophytic ones during the Late Miocene (Puerto Madryn Formation). The subtribe Nassauviinae comprises 25 genera and ca. 320 species of vines, shrubs and low trees endemic to America with a wide range of ecological preferences; the nearest living relatives of the fossil types being mostly confined to humid landscapes. The unusual occurrence of these groups during the arid characterized Late Miocene time could be attributed to the complex interplay of the mountain uplift and global circulation patterns. These forcing factors would have created a mosaic of different habitats with both patches of forest and dry-adapted species developing in relatively small regions. This is the first fossil record of Nassauviinae and confirms that this subtribe of Asteraceae was already differentiated in the Miocene.  相似文献   

20.
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