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Gerhard Wiegleb - One of the best experts on this subject based on the ideXlab platform.
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die neubearbeitung der familie Potamogetonaceae und der sektion batrachium ranunculus ranunculaceae kommentare und erganzungen zur 22 auflage der rothmaler exkursionsflora von deutschland grundband 2019 erster beitrag
Schlechtendalia, 2018Co-Authors: Gerhard WieglebAbstract:Wiegleb, G. 2018: Die Neubearbeitung der Familie Potamogetonaceae und der Sektion Batrachium (Ranunculus, Ranunculaceae). Kommentare und Erganzungen zur 22. Auflage der Rothmaler Exkursionsflora von Deutschland – Grundband, 2019: Erster Beitrag. Schlechtendalia 35: 47–63. Innerhalb der Potamogetonaceae werden erstmals die Gattungen Potamogeton und Stuckenia unterschieden. Die Subspezies der Gattung Zannichellia werden neu gefasst und verschlusselt. Innerhalb der Sektion Batrachium werden die Arten neu verschlusselt. Ranunculus tripartitus und R. confervoides werden nicht mehr gelistet. Die Chromosomenzahlen werden kritisch revidiert. Die Bearbeitung folgt einem strikt morphologischen Artkonzept. Die bisherigen Unterarten von R. peltatus und R. penicillatus werden als eigenstandige Arten gefuhrt. Einige Arten (etwa R. saniculifolius und R. rionii) sind haufiger als bisher angenommen, wahrend R. aquatilis und R. pseudofluitans seltener sind. Die genaue Verbreitung der meisten Taxa ist aufgrund von Mechanismen wie phanotypischer Plastizitat, haufiger Hybridisierung und Polyploidisierung allerdings nur unzureichend bekannt. Einige Bestimmungshilfen fur die sichere Ansprache der Arten werden tabellarisch zusammengefasst.
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die neubearbeitung der familie Potamogetonaceae und der sektion batrachium ranunculus ranunculaceae
Schlechtendalia, 2018Co-Authors: Gerhard WieglebAbstract:Wiegleb, G. 2018: Die Neubearbeitung der Familie Potamogetonaceae und der Sektion Batrachium (Ranunculus, Ranunculaceae). Kommentare und Erganzungen zur 22. Auflage der Rothmaler Exkursionsflora von Deutschland – Grundband, 2019: Erster Beitrag. Schlechtendalia 35: 47–63. Innerhalb der Potamogetonaceae werden erstmals die Gattungen Potamogeton und Stuckenia unterschieden. Die Subspezies der Gattung Zannichellia werden neu gefasst und verschlusselt. Innerhalb der Sektion Batrachium werden die Arten neu verschlusselt. Ranunculus tripartitus und R. confervoides werden nicht mehr gelistet. Die Chromosomenzahlen werden kritisch revidiert. Die Bearbeitung folgt einem strikt morphologischen Artkonzept. Die bisherigen Unterarten von R. peltatus und R. penicillatus werden als eigenstandige Arten gefuhrt. Einige Arten (etwa R. saniculifolius und R. rionii) sind haufiger als bisher angenommen, wahrend R. aquatilis und R. pseudofluitans seltener sind. Die genaue Verbreitung der meisten Taxa ist aufgrund von Mechanismen wie phanotypischer Plastizitat, haufiger Hybridisierung und Polyploidisierung allerdings nur unzureichend bekannt. Einige Bestimmungshilfen fur die sichere Ansprache der Arten werden tabellarisch zusammengefasst.
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synopsis of Potamogetonaceae in iran with supplements to the flora iranica and a new identification key
Phytotaxa, 2017Co-Authors: Shabnam Abbasi, Saeed Afsharzadeh, Mehri Dinarvand, Gerhard WieglebAbstract:Potamogetonaceae comprises three closely related genera: Potamogeton , Stuckenia and Groenlandia . The last comprehensive research on this species group in Iran dates back to 1971 ( Flora Iranica ). In this research we present an identification key to the Potamogetonaceae species in Iran with descriptions of all taxa based on morphological and anatomical studies. 11 species of Potamogeton, three species of Stuckenia and one of Groenlandia are described from Iran. Moreover, a new hybrid ( P. pusillus × P. crispus ) is described as a new to science. Distribution is outlined for all taxa. The genus Potamogeton and related genera have a wide distribution in different aquatic ecosystems in particular of northern, central and southwestern Iran. The species formerly recorded as P. alpinus was identified as P. schweinfurthii. It is recorded for the flora of Iran for the first time.
Richard J. Gornall - One of the best experts on this subject based on the ideXlab platform.
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molecular confirmation of potamogeton bottnicus p pectinatus p vaginatus Potamogetonaceae in britain
Web Science, 2001Co-Authors: R A King, Richard J. Gornall, C D Preston, J M CroftAbstract:Abstract Restriction fragment length polymorphisms in the internal transcribed spacer region of ribosomal DNA and in the chloroplast genome combine to confirm the existence of Potamogeton × bottnicus ( P. pectinatus × P. vaginatus ) in Britain. One of the parents, P. vaginatus , is not currently a member of the British flora, but did occur here in the past (the latest fossil fruits date from 30 000 BP) and the hybrid may therefore owe its origin to ancient cross-pollination involving indigenous material or to more recent long-distance dispersal.
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euploid and aneuploid evolution in potamogeton Potamogetonaceae a factual basis for interpretation
Web Science, 1998Co-Authors: Peter M. Hollingsworth, C D Preston, Richard J. GornallAbstract:In a review of chromosome numbers in the genus Potamogeton, we highlight numerous errors that have crept into the literature. These have resulted chiefly from reliance on abstracts in chromosome number indices and compilations, rather than on the original publications, but partly also because of misleading summaries even in the primary literature. We present a list of counts that we believe are original and genuine, and a list of those that were never made but which nevertheless appear in the literature. Scrutiny of the list of accepted counts indicates that aneuploidy is widespread in the genus and that transition between the two common chromosome numbers (2n=26 and 2n=28) has occurred several times. Currently available data are insufficient to resolve the question of the ancestral base number. We also present details of the first chromosome counts from English populations of five taxa: P. polygonifolius Pourr. (2n=28), P. pectinatus L. (2n=ca. 78), P. perfoliatus L. (2n=ca. 52), P.×nitens Weber (P. gramineus×P. perfoliatus) (2n=ca. 52) and P.×salicifolius Wolfg. (P. lucens×P. perfoliatus) (2n=ca. 52).
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lack of detectable isozyme variability in british populations of potamogeton epihydrus Potamogetonaceae
Web Science, 1998Co-Authors: Peter M. Hollingsworth, C D Preston, Richard J. GornallAbstract:Outside North America Potamogeton epihydrus Raf. is confined to two areas of Britain. An investigation of British material from apparently native sites in the Outer Hebrides and from a canal in northern England (where it is believed to be introduced) revealed only a single isozyme genotype. Ten putative loci were resolved. The IDH phenotype was uniform and three-banded, consistent with heterozygosity (possibly caused by a duplicated locus or preserved by clonal growth). All other enzyme loci were homozygous.
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isozyme evidence for the parentage and multiple origins ofpotamogeton suecicus p pectinatus p filiformis Potamogetonaceae
Plant Systematics and Evolution, 1996Co-Authors: Peter M. Hollingsworth, C D Preston, Richard J. GornallAbstract:Evidence from isozyme analyses indicates thatPotamogeton ×suecicus is the hybrid betweenP. pectinatus andP. filiformis. The hybrid appears to have arisen on several occasions. The isozyme profiles of this hybrid from the Rivers Wharfe and Ure in Yorkshire, south of the present limit of distribution ofP. filiformis, suggest that each population is a single clone; these clones may be relics from the Weichselian glacial period. Populations of the putative hybrid from the Rivers Tweed and Till are notP. ×suecicus but probably haveP. vaginatus andP. pectinatus as parents. If so, this is a remarkable example of a pondweed hybrid persisting vegetatively in an area outside the distributional range of one of its parents.
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Genetic variability in two hydrophilous species of Potamogeton, P. pectinatus and P. filiformis (Potamogetonaceae)
1996Co-Authors: Peter M. Hollingsworth, Christopher D. Preston, Richard J. GornallAbstract:Genetic variability inPotamogeton pectinatus andP. filiformis was studied by means of isozymes. The overall levels of variability were similar to some other well studied hydrophilous species, and were shown to be distributed more between than within populations. This partitioning of variability was attributed to three main factors. (1) Clonal growth (as measured by the frequency of multi-enzyme phenotypes) was shown to be a major factor in both species, although more important inP. pectinatus. (2) Low levels of sexual reproduction were shown to be a likely contributor to the partitioning of variability inP. pectinatus; such reproduction is probably limited by seedling recruitment rather than by infrequent flowering. (3) Geographical isolation was indicated as a factor regulating gene flow at distances of more than about 1000 km in both species, with the data suggesting that dispersal between populations is mainly by seed rather than by vegetative means.
Peter M. Hollingsworth - One of the best experts on this subject based on the ideXlab platform.
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euploid and aneuploid evolution in potamogeton Potamogetonaceae a factual basis for interpretation
Web Science, 1998Co-Authors: Peter M. Hollingsworth, C D Preston, Richard J. GornallAbstract:In a review of chromosome numbers in the genus Potamogeton, we highlight numerous errors that have crept into the literature. These have resulted chiefly from reliance on abstracts in chromosome number indices and compilations, rather than on the original publications, but partly also because of misleading summaries even in the primary literature. We present a list of counts that we believe are original and genuine, and a list of those that were never made but which nevertheless appear in the literature. Scrutiny of the list of accepted counts indicates that aneuploidy is widespread in the genus and that transition between the two common chromosome numbers (2n=26 and 2n=28) has occurred several times. Currently available data are insufficient to resolve the question of the ancestral base number. We also present details of the first chromosome counts from English populations of five taxa: P. polygonifolius Pourr. (2n=28), P. pectinatus L. (2n=ca. 78), P. perfoliatus L. (2n=ca. 52), P.×nitens Weber (P. gramineus×P. perfoliatus) (2n=ca. 52) and P.×salicifolius Wolfg. (P. lucens×P. perfoliatus) (2n=ca. 52).
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lack of detectable isozyme variability in british populations of potamogeton epihydrus Potamogetonaceae
Web Science, 1998Co-Authors: Peter M. Hollingsworth, C D Preston, Richard J. GornallAbstract:Outside North America Potamogeton epihydrus Raf. is confined to two areas of Britain. An investigation of British material from apparently native sites in the Outer Hebrides and from a canal in northern England (where it is believed to be introduced) revealed only a single isozyme genotype. Ten putative loci were resolved. The IDH phenotype was uniform and three-banded, consistent with heterozygosity (possibly caused by a duplicated locus or preserved by clonal growth). All other enzyme loci were homozygous.
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isozyme evidence for the parentage and multiple origins ofpotamogeton suecicus p pectinatus p filiformis Potamogetonaceae
Plant Systematics and Evolution, 1996Co-Authors: Peter M. Hollingsworth, C D Preston, Richard J. GornallAbstract:Evidence from isozyme analyses indicates thatPotamogeton ×suecicus is the hybrid betweenP. pectinatus andP. filiformis. The hybrid appears to have arisen on several occasions. The isozyme profiles of this hybrid from the Rivers Wharfe and Ure in Yorkshire, south of the present limit of distribution ofP. filiformis, suggest that each population is a single clone; these clones may be relics from the Weichselian glacial period. Populations of the putative hybrid from the Rivers Tweed and Till are notP. ×suecicus but probably haveP. vaginatus andP. pectinatus as parents. If so, this is a remarkable example of a pondweed hybrid persisting vegetatively in an area outside the distributional range of one of its parents.
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Genetic variability in two hydrophilous species of Potamogeton, P. pectinatus and P. filiformis (Potamogetonaceae)
1996Co-Authors: Peter M. Hollingsworth, Christopher D. Preston, Richard J. GornallAbstract:Genetic variability inPotamogeton pectinatus andP. filiformis was studied by means of isozymes. The overall levels of variability were similar to some other well studied hydrophilous species, and were shown to be distributed more between than within populations. This partitioning of variability was attributed to three main factors. (1) Clonal growth (as measured by the frequency of multi-enzyme phenotypes) was shown to be a major factor in both species, although more important inP. pectinatus. (2) Low levels of sexual reproduction were shown to be a likely contributor to the partitioning of variability inP. pectinatus; such reproduction is probably limited by seedling recruitment rather than by infrequent flowering. (3) Geographical isolation was indicated as a factor regulating gene flow at distances of more than about 1000 km in both species, with the data suggesting that dispersal between populations is mainly by seed rather than by vegetative means.
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genetic variability in british populations ofpotamogeton coloratus Potamogetonaceae
Web Science, 1995Co-Authors: Peter M. Hollingsworth, Richard J. Gornall, C D PrestonAbstract:The partitioning of genetic variability within and between twelve British populations of the anemophilous aquaticPotamogeton coloratusHornem. was investigated by isozyme analysis. Low levels of variability as measured by P, A and H were found. Calculation of Wright's F statistics revealed a high mean value of the overall inbreeding coefficient, (FIT = 0.939), which was attributed both to high levels of genetic subdivision among populations (mean FST = 0.702) and to a high frequency of inbreeding or clonal growth within them (mean FIS = 0.796). Only two populations are polymorphic; both inhabit sites with a long post-glacial history as wetlands. Populations of recent origin, as well as some of older vintage, contain only a single multi-locus isozyme genotype, homozygous at all loci except for IDH. A genetic bottleneck following the Devensian glaciation is discussed as a possible cause of the pattern of variation. Evidence for a duplicated IDH locus is presented.
Zdenek Kaplan - One of the best experts on this subject based on the ideXlab platform.
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Taxonomic identity and typification of selected names of North American Potamogetonaceae
Brittonia, 2013Co-Authors: Zdenek Kaplan, James L RevealAbstract:Most names in North American Potamogetonaceae have not been typified. Details of typifications are given for 72 names based on North American material published in the genus Potamogeton mainly by North American botanists. All names are reviewed for their nomenclatural validity and legitimacy, and interpreted taxonomically. Holotypes are indicated for 31 names and previously declared lectotypes or neotypes are listed for eight names. Lectotypes are designated for 24 previously untypified names and step-2 lectotypifications are proposed for three names that were based on heterogeneous material. Type material for three Rafinesque names and one proposed by Wood have not been located. An annotated list provides collection data, type status, homotypic synonyms, and currently accepted names. Two names are excluded from Potamogeton , being based on species of Myriophyllum (Haloragaceae).
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multivariate morphometric analysis of the potamogeton compressus group Potamogetonaceae
Botanical Journal of the Linnean Society, 2012Co-Authors: Zdenek Kaplan, Karol MarholdAbstract:The Potamogeton compressus group is a complex of three to five closely related species with a circumpolar distribution in the Northern Hemisphere. Multivariate morphometric analyses (principal component analysis, cluster analysis, canonical and classificatory discriminant analyses) were used to elucidate the patterns of variation within this group and to test the morphological differentiation of the species recognized in the current literature. From the entire distribution range, 156 specimens of the group were included in the numerical methods. Results from morphological comparison are discussed in relation to molecular data, reproductive behaviour and geographical distribution. Morphometric analyses provided evidence that this complex can be clearly divided into three groups, one of which was subdivided mainly on the basis of allopatric occurrence and genetic differentiation. These groups correspond to four species accepted here: P. acutifolius (temperate regions of Europe), P. compressus (boreal and temperate regions of Europe and Asia), P. manchuriensis (northeastern China and Russian Far East) and P. zosteriformis (boreal and temperate regions of North America). Two species, P. acutifolius and P. compressus, are partly sympatric, but clearly differentiated morphologically and genetically, and effectively isolated reproductively. Endemic P. manchuriensis is characterized by a unique combination of characters and an occurrence in a limited geographical area. Allopatric P. zosteriformis is weakly differentiated morphologically from P. compressus, but differs markedly in molecular markers correlated with geographical differentiation. It may represent a cryptic species. In contrast, a recently suggested concept of southern Siberian P. henningii was not supported by our analyses. Plants so named are considered here as slender phenotypes of the widespread and variable P. compressus. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 170, 112‐130. ADDITIONAL KEYWORDS: aquatic plants ‐ differentiation ‐ numerical taxonomy ‐ species complex ‐ species delimitation ‐ variation.
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1638 proposal to conserve the name potamogeton schweinfurthii a benn Potamogetonaceae with a conserved type
Taxon, 2004Co-Authors: Zdenek Kaplan, Jeanjacques SymoensAbstract:Potamogeton schweinfurthii A. Benn. is the name generally applied to a rather common and widely distributed species in Africa and on several surrounding islands. Soon after it was first proposed by Bennett (1.c.), the name was adopted in the world-wide revision of the genus by Graebner (in Engler, Pflanzenr. 31 (IV.11): 79. 1907). Since then, it has been adopted in all relevant literature (e.g., Dandy, J. Linn. Soc., Bot. 50: 526. 1937; Berhaut, Fl. Senegal 81. 1954; Andrews Flow. Pl. Sudan 3: 234. 1956; Ozenda, Fl. Sahara Sept. Centr. 126. 1958; Obermayer in Codd et al., Fl. South. Afr. 1: 66. 1966; Berhaut, Fl. Senegal ed. 2: 180. 1967; Hepper, Fl. West Trop. Afr., ed. 2, 3: 16 1968; Denny et Lye, Kew Bull. 28: 117-120. 1973; Lisowski et al., Fl. Afr. Centr., Potamogetonaceae 6. 1978; Symoens, Fl. Cameroun 26: 60. 1984; Jafri in Jafri et El-Gadi, Fl. Libya 5. 1984; Wiegleb, Feddes Repert. 99: 259. 1988; Lye in Thulin, Fl. Somalia 4: 14. 1995; Wiegleb, Willdenowia 25: 55. 1995; Lye in Edwards et al., Fl. Ethiopia Eritrea 6: 23. 1997; Wiegleb et Kaplan, Folia Geobot. 33: 273. 1998). This species is closely related to the Eurasian P lucens L. with which it shares many important morphological and anatomical characters. Potamogeton schweinfurthii has submerged leaves sessile to shortly petiolate (mostly 0-3 cm), with acute to mucronate apex, and floating leaves sometimes developed but mostly not present in adult fertile plants. The stem anatomy pattern of this species shows the endodermis of U-type, interlacunar bundles present and subepidermal bundles absent or scattered ones present (see Wiegleb in Flora 184: 198-200. 1990 and Wiegleb et Kaplan in Folia Geobot. 33: 248. 1998 for a detailed explanation of anatomical structures and terminology). Potamogeton schweinfurthii is in Africa sometimes confused with P nodosus Poir. Even though this latter species is in some of its phenotypes very similar to P schweinfurthii, it is actually not closely related but occupies within the genus a rather isolated position together with the East-Asian P distinctus A. Benn. In contrast to
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phenotypic plasticity in potamogeton Potamogetonaceae
Folia Geobotanica, 2002Co-Authors: Zdenek KaplanAbstract:Sources of the extensive morphological variation of the species and hybrids ofPotamogeton were studied, especially from the viewpoint of the stability of the morphological characters used inPotamogeton taxonomy. Transplant experiments, the cultivation of clones under different values of environmental factors, and the cultivation of different clones under uniform conditions were performed to assess the proportion of phenotypic plasticity in the total morphological variation. Samples from 184 populations of 41Potamogeton taxa were grown. The immense range of phenotypic plasticity, which is possible for a single clone, is documented in detail in 14 well-described examples. The differences among distinct populations of a single species observed in the field were mostly not maintained when grown together under the same environmental conditions. Clonal material cultivated under different values of environmental factors produced distinct phenotypes, and in a few cases a single genotype was able to demonstrate almost the entire range of morphological variation in an observed trait known for that species. Several characters by recent literature claimed to be suitable for distinguishing varieties or even species were proven to be dependent on environmental conditions and to be highly unreliable markers for the delimiation of taxa. The unsatisfactory taxonomy that results when such classification of phenotypes is adopted is illustrated by three examples from recent literature. Phenotypic plasticity was found to be the main source of morphological variation within the species ofPotamogeton, having much more influence than morphological differences caused by different genotypes.
C D Preston - One of the best experts on this subject based on the ideXlab platform.
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regular articlemolecular confirmation of potamogeton bottnicus p pectinatus p vaginatus Potamogetonaceae in britain
Botanical Journal of the Linnean Society, 2001Co-Authors: R A King, C D Preston, J M CroftAbstract:Restriction fragment length polymorphisms in the internal transcribed spacer region of ribosomal DNA and in the chloroplast genome combine to confirm the existence of Potamogeton×bottnicus (P. pectinatus×P. vaginatus) in Britain. One of the parents, P. vaginatus, is not currently a member of the British flora, but did occur here in the past (the latest fossil fruits date from 30 000 BP) and the hybrid may therefore owe its origin to ancient cross-pollination involving indigenous material or to more recent long-distance dispersal.
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molecular confirmation of potamogeton bottnicus p pectinatus p vaginatus Potamogetonaceae in britain
Web Science, 2001Co-Authors: R A King, Richard J. Gornall, C D Preston, J M CroftAbstract:Abstract Restriction fragment length polymorphisms in the internal transcribed spacer region of ribosomal DNA and in the chloroplast genome combine to confirm the existence of Potamogeton × bottnicus ( P. pectinatus × P. vaginatus ) in Britain. One of the parents, P. vaginatus , is not currently a member of the British flora, but did occur here in the past (the latest fossil fruits date from 30 000 BP) and the hybrid may therefore owe its origin to ancient cross-pollination involving indigenous material or to more recent long-distance dispersal.
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euploid and aneuploid evolution in potamogeton Potamogetonaceae a factual basis for interpretation
Web Science, 1998Co-Authors: Peter M. Hollingsworth, C D Preston, Richard J. GornallAbstract:In a review of chromosome numbers in the genus Potamogeton, we highlight numerous errors that have crept into the literature. These have resulted chiefly from reliance on abstracts in chromosome number indices and compilations, rather than on the original publications, but partly also because of misleading summaries even in the primary literature. We present a list of counts that we believe are original and genuine, and a list of those that were never made but which nevertheless appear in the literature. Scrutiny of the list of accepted counts indicates that aneuploidy is widespread in the genus and that transition between the two common chromosome numbers (2n=26 and 2n=28) has occurred several times. Currently available data are insufficient to resolve the question of the ancestral base number. We also present details of the first chromosome counts from English populations of five taxa: P. polygonifolius Pourr. (2n=28), P. pectinatus L. (2n=ca. 78), P. perfoliatus L. (2n=ca. 52), P.×nitens Weber (P. gramineus×P. perfoliatus) (2n=ca. 52) and P.×salicifolius Wolfg. (P. lucens×P. perfoliatus) (2n=ca. 52).
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lack of detectable isozyme variability in british populations of potamogeton epihydrus Potamogetonaceae
Web Science, 1998Co-Authors: Peter M. Hollingsworth, C D Preston, Richard J. GornallAbstract:Outside North America Potamogeton epihydrus Raf. is confined to two areas of Britain. An investigation of British material from apparently native sites in the Outer Hebrides and from a canal in northern England (where it is believed to be introduced) revealed only a single isozyme genotype. Ten putative loci were resolved. The IDH phenotype was uniform and three-banded, consistent with heterozygosity (possibly caused by a duplicated locus or preserved by clonal growth). All other enzyme loci were homozygous.
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isozyme evidence for the parentage and multiple origins ofpotamogeton suecicus p pectinatus p filiformis Potamogetonaceae
Plant Systematics and Evolution, 1996Co-Authors: Peter M. Hollingsworth, C D Preston, Richard J. GornallAbstract:Evidence from isozyme analyses indicates thatPotamogeton ×suecicus is the hybrid betweenP. pectinatus andP. filiformis. The hybrid appears to have arisen on several occasions. The isozyme profiles of this hybrid from the Rivers Wharfe and Ure in Yorkshire, south of the present limit of distribution ofP. filiformis, suggest that each population is a single clone; these clones may be relics from the Weichselian glacial period. Populations of the putative hybrid from the Rivers Tweed and Till are notP. ×suecicus but probably haveP. vaginatus andP. pectinatus as parents. If so, this is a remarkable example of a pondweed hybrid persisting vegetatively in an area outside the distributional range of one of its parents.