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Peter Leins - One of the best experts on this subject based on the ideXlab platform.

  • An analysis of the early floral development of Pittosporum tobira (THUNB.) AITON and some remarks on the systematic position of the family Pittosporaceae
    Feddes Repertorium, 2008
    Co-Authors: Claudia Erbar, Peter Leins
    Abstract:

    In Pittosporum tobira all floral organs are initiated in a strictly acropetal succession. It is striking that sepals and petals show an extremely early hyponastical development. Important floral characters for placing the family Pittosporaceae near the Apiales (Araliaceae and Apiaceae) are the early sympetaly, only gradual differences in the gynoecium development and placentation, and the fact that a nectar secreting area is situated at the base of the dorsal carpel flanks (ovary superior in Pittosporaceae, inferior in Apiales). Viscid latex, which plays an important role in the dispersal of the seeds by exozoochory, is produced by the multicellular epidermal hairs in the septal (placental) region. Bei Pittosporum tobira werden alle Blutenorgane in einer streng akropetalen Folge am Blutenvegetationskegel ausgegliedert. Auffallig ist die extrem fruhe hyponastische Krummung der Sepalen und Petalen. Die u. a. von Seiten der molekularen Systematik postulierte Verwandtschaft der Pittosporaceae mit den Apiales (Araliaceae und Apiaceae) wird aus blutenontogenetischer und -morphologischer Sicht unterstutzt. Wichtige Argumente sind: die fruhe Sympetalie, die nur graduellen Unterschiede in der Gynoecealentwicklung und in der Plazentation sowie die Lage des Nektar sezernierenden Bereichs an der Basis der dorsalen Karpellflanken (Ovar oberstandig bei den Pittosporaceae, unterstandig bei den Apiales). Wir konnen annehmen, das die Araliaceae, Apiaceae und Pittosporaceae sowie letztlich die Campanulales-Asterales auf einen gemeinsamen Ursprung zuruckgehen. Legt man weniger Gewicht auf chemische Merkmale, dann kann man vielleicht sogar – im Moment noch etwas spekulativ – zusatzlich die Cornales auf diesen Grundstock zuruckfuhren. Der klebrige Milchsaft, der eine wichtige Rolle bei der Ausbreitung der Samen durch Vogel spielt, wird bei Pittosporum von mehrzelligen Epidermishaaren im Bereich der Septen- (Plazentar-)Region produziert.

  • Sympetaly in Apiales (Apiaceae, Araliaceae, Pittosporaceae)
    South African Journal of Botany, 2004
    Co-Authors: Claudia Erbar, Peter Leins, Patricia M. Tilney
    Abstract:

    In all recent molecular sequence based analyses Apiales come out to be placed within a broadly defined group Asteridae. Within 'euasterids II' Apiales (Apiaceae, Araliaceae, Pittosporaceae, Aralidiaceae, as well as some former cornaceous taxa) form a monophyletic group in a position close to Asterales-Campanulales and Dipsacales. Also from a floral developmental point of view the mostly choripetalous Apiales are not out of place among these sympetalous orders: In members of Apiales (Apiaceae: Hydrocotyle; Araliaceae: Aralia, Hedera; Pittosporaceae: Sollya, Pittosporum) the corollas are initiated from a continuous ring primordium corresponding exactly to the development in Campanulales-Asterales and Dipsacales. Only in Pittosporaceae further growth of this primordium results in a weak sympetaly in adult flowers. Molecular data suggest that the subfamily Hydrocotyloideae is polyphyletic, with Hydrocotyle belonging to the lineage not placed within Apiaceae but more closely related to Araliaceae, a position fitting well with the mode of formation of the corolla.

  • Floral organ sequences in Apiales (Apiaceae, Araliaceae, Pittosporaceae)
    South African Journal of Botany, 2004
    Co-Authors: Peter Leins, Claudia Erbar, Patricia M. Tilney
    Abstract:

    It is remarkable that families like Apiaceae and Brassicaceae, characterised by uniform floral diagrams (i.e. stable positioning of floral organs relative to one another), show a great variability in initiation sequence of the floral organs. Within the subfamily Saniculoideae of the Apiaceae temporal overlaps in the initiation of the floral whorls (Astrantia), the formation of common stamen-sepal primordia (Astrantia), and segmentation in the formation of petals in pairs (Sanicula) occur. Reduction of the calyx and shortening of the plastochrons toward zero are trends found in the more advanced Apioideae (Foeniculum, Levisticum). Hydrocotyle, with its early sympetaly, resembles the Araliaceae more closely. Of interest is the fact that in Araliaceae the flower orientation is variable. Sometimes one sepal is opposite the subtending bract, a feature which becomes fixed in Cyphiaceae and Lobeliaceae of Campanulales, a sister group of Apiales.

  • the pollen box in cyphiaceae Campanulales
    International Journal of Plant Sciences, 2003
    Co-Authors: Peter Leins, Claudia Erbar
    Abstract:

    In the flower of the monogeneric family Cyphiaceae, distributed in tropical and southern Africa, a pollen box is formed by the five connivent anthers and the headlike style tip as bottom. Pollen with abundant pollenkitt is released into this box just before anthesis. The flowers either have a salverform shape or are bilabiate with three petals forming the upper lip; transitions between these flower types can also be observed. On the flower biology, we only can speculate the following: (1) Flowers with the pollen box represent the (perhaps long‐lasting) male phase of anthesis. (2) In the female phase, the anthers are spreading and the mouth of the stylar channel opens presumably by disintegration of closing hairs. A mucilaginous secretion coming out of the mouth may receive the pollen from pollinators. (3) Pollinators of the salverform flowers are presumably butterflies, whereas pollinators of bilabiate flowers are bees. (4) Pollen is presumably applied at the proboscis of the butterflies that comes in con...

  • portioned pollen release and the syndromes of secondary pollen presentation in the Campanulales asterales complex11 dedicated in friendship to prof dr andreas sievers on the occasion of his 65th birthday june 21 1996
    Flora, 1995
    Co-Authors: Claudia Erbar, Peter Leins
    Abstract:

    Summary The release of pollen in portions, i. e. limiting the pollen removed by individual pollinators during a single visit, is a widespread phenomenon. The biological significance of this phenomenon is that it helps to optimize the pollination. Parameters like number of ovules, number of application sites to the pollinator or spectrum of pollinators, which may be correlated with the size of the pollen portion, are illustrated as a net of possible correlations (Fig. 1). Apart from pollenkitt, viscin or cellulosic threads and the non-simultaneous opening of the anthers, the secondary pollen presentation is a special mechanism of pollen portioning. Secondary pollen presentation occurs in several dicotyledonous and in a few monocotyledonous families. Its occurrence is a distinctive feature in the Campanulales-Asterales -complex. The different mechanisms in the Campanulales-Asterales ( Asteraceae, Lobeliaceae, Campanulaceae, Goodeniaceae, Brunoniaceae, Calyceraceae ) are briefly described. The differentiations of the "basic syndrome" (radial symmetry of the flower bud, complete androecial whorl, introrse anthers, the latter connivent at the time of dehiscence, proterandry, late and sequential growth of filaments and style) are presented in two diagrams (Figs. 30 + 31). In addition, a few remarks are given on pollen presentation in Rubiaceae, Cyphiaceae, Sphenocieaceae, Pentaphragmataceae, Stylidiaceae , of which the latter four are usually assigned to Campanulales-Asterales .

Claudia Erbar - One of the best experts on this subject based on the ideXlab platform.

  • An analysis of the early floral development of Pittosporum tobira (THUNB.) AITON and some remarks on the systematic position of the family Pittosporaceae
    Feddes Repertorium, 2008
    Co-Authors: Claudia Erbar, Peter Leins
    Abstract:

    In Pittosporum tobira all floral organs are initiated in a strictly acropetal succession. It is striking that sepals and petals show an extremely early hyponastical development. Important floral characters for placing the family Pittosporaceae near the Apiales (Araliaceae and Apiaceae) are the early sympetaly, only gradual differences in the gynoecium development and placentation, and the fact that a nectar secreting area is situated at the base of the dorsal carpel flanks (ovary superior in Pittosporaceae, inferior in Apiales). Viscid latex, which plays an important role in the dispersal of the seeds by exozoochory, is produced by the multicellular epidermal hairs in the septal (placental) region. Bei Pittosporum tobira werden alle Blutenorgane in einer streng akropetalen Folge am Blutenvegetationskegel ausgegliedert. Auffallig ist die extrem fruhe hyponastische Krummung der Sepalen und Petalen. Die u. a. von Seiten der molekularen Systematik postulierte Verwandtschaft der Pittosporaceae mit den Apiales (Araliaceae und Apiaceae) wird aus blutenontogenetischer und -morphologischer Sicht unterstutzt. Wichtige Argumente sind: die fruhe Sympetalie, die nur graduellen Unterschiede in der Gynoecealentwicklung und in der Plazentation sowie die Lage des Nektar sezernierenden Bereichs an der Basis der dorsalen Karpellflanken (Ovar oberstandig bei den Pittosporaceae, unterstandig bei den Apiales). Wir konnen annehmen, das die Araliaceae, Apiaceae und Pittosporaceae sowie letztlich die Campanulales-Asterales auf einen gemeinsamen Ursprung zuruckgehen. Legt man weniger Gewicht auf chemische Merkmale, dann kann man vielleicht sogar – im Moment noch etwas spekulativ – zusatzlich die Cornales auf diesen Grundstock zuruckfuhren. Der klebrige Milchsaft, der eine wichtige Rolle bei der Ausbreitung der Samen durch Vogel spielt, wird bei Pittosporum von mehrzelligen Epidermishaaren im Bereich der Septen- (Plazentar-)Region produziert.

  • Sympetaly in Apiales (Apiaceae, Araliaceae, Pittosporaceae)
    South African Journal of Botany, 2004
    Co-Authors: Claudia Erbar, Peter Leins, Patricia M. Tilney
    Abstract:

    In all recent molecular sequence based analyses Apiales come out to be placed within a broadly defined group Asteridae. Within 'euasterids II' Apiales (Apiaceae, Araliaceae, Pittosporaceae, Aralidiaceae, as well as some former cornaceous taxa) form a monophyletic group in a position close to Asterales-Campanulales and Dipsacales. Also from a floral developmental point of view the mostly choripetalous Apiales are not out of place among these sympetalous orders: In members of Apiales (Apiaceae: Hydrocotyle; Araliaceae: Aralia, Hedera; Pittosporaceae: Sollya, Pittosporum) the corollas are initiated from a continuous ring primordium corresponding exactly to the development in Campanulales-Asterales and Dipsacales. Only in Pittosporaceae further growth of this primordium results in a weak sympetaly in adult flowers. Molecular data suggest that the subfamily Hydrocotyloideae is polyphyletic, with Hydrocotyle belonging to the lineage not placed within Apiaceae but more closely related to Araliaceae, a position fitting well with the mode of formation of the corolla.

  • Floral organ sequences in Apiales (Apiaceae, Araliaceae, Pittosporaceae)
    South African Journal of Botany, 2004
    Co-Authors: Peter Leins, Claudia Erbar, Patricia M. Tilney
    Abstract:

    It is remarkable that families like Apiaceae and Brassicaceae, characterised by uniform floral diagrams (i.e. stable positioning of floral organs relative to one another), show a great variability in initiation sequence of the floral organs. Within the subfamily Saniculoideae of the Apiaceae temporal overlaps in the initiation of the floral whorls (Astrantia), the formation of common stamen-sepal primordia (Astrantia), and segmentation in the formation of petals in pairs (Sanicula) occur. Reduction of the calyx and shortening of the plastochrons toward zero are trends found in the more advanced Apioideae (Foeniculum, Levisticum). Hydrocotyle, with its early sympetaly, resembles the Araliaceae more closely. Of interest is the fact that in Araliaceae the flower orientation is variable. Sometimes one sepal is opposite the subtending bract, a feature which becomes fixed in Cyphiaceae and Lobeliaceae of Campanulales, a sister group of Apiales.

  • the pollen box in cyphiaceae Campanulales
    International Journal of Plant Sciences, 2003
    Co-Authors: Peter Leins, Claudia Erbar
    Abstract:

    In the flower of the monogeneric family Cyphiaceae, distributed in tropical and southern Africa, a pollen box is formed by the five connivent anthers and the headlike style tip as bottom. Pollen with abundant pollenkitt is released into this box just before anthesis. The flowers either have a salverform shape or are bilabiate with three petals forming the upper lip; transitions between these flower types can also be observed. On the flower biology, we only can speculate the following: (1) Flowers with the pollen box represent the (perhaps long‐lasting) male phase of anthesis. (2) In the female phase, the anthers are spreading and the mouth of the stylar channel opens presumably by disintegration of closing hairs. A mucilaginous secretion coming out of the mouth may receive the pollen from pollinators. (3) Pollinators of the salverform flowers are presumably butterflies, whereas pollinators of bilabiate flowers are bees. (4) Pollen is presumably applied at the proboscis of the butterflies that comes in con...

  • portioned pollen release and the syndromes of secondary pollen presentation in the Campanulales asterales complex11 dedicated in friendship to prof dr andreas sievers on the occasion of his 65th birthday june 21 1996
    Flora, 1995
    Co-Authors: Claudia Erbar, Peter Leins
    Abstract:

    Summary The release of pollen in portions, i. e. limiting the pollen removed by individual pollinators during a single visit, is a widespread phenomenon. The biological significance of this phenomenon is that it helps to optimize the pollination. Parameters like number of ovules, number of application sites to the pollinator or spectrum of pollinators, which may be correlated with the size of the pollen portion, are illustrated as a net of possible correlations (Fig. 1). Apart from pollenkitt, viscin or cellulosic threads and the non-simultaneous opening of the anthers, the secondary pollen presentation is a special mechanism of pollen portioning. Secondary pollen presentation occurs in several dicotyledonous and in a few monocotyledonous families. Its occurrence is a distinctive feature in the Campanulales-Asterales -complex. The different mechanisms in the Campanulales-Asterales ( Asteraceae, Lobeliaceae, Campanulaceae, Goodeniaceae, Brunoniaceae, Calyceraceae ) are briefly described. The differentiations of the "basic syndrome" (radial symmetry of the flower bud, complete androecial whorl, introrse anthers, the latter connivent at the time of dehiscence, proterandry, late and sequential growth of filaments and style) are presented in two diagrams (Figs. 30 + 31). In addition, a few remarks are given on pollen presentation in Rubiaceae, Cyphiaceae, Sphenocieaceae, Pentaphragmataceae, Stylidiaceae , of which the latter four are usually assigned to Campanulales-Asterales .

Jeffrey D. Palmer - One of the best experts on this subject based on the ideXlab platform.

  • the chloroplast genome arrangement of lobelia thuliniana lobeliaceae expansion of the inverted repeat in an ancestor of the Campanulales
    Plant Systematics and Evolution, 1999
    Co-Authors: Eric B. Knox, Jeffrey D. Palmer
    Abstract:

    A clone-bank ofSac I restriction fragments was constructed from the chloroplast DNA (cpDNA) ofLobelia thulinianaE. B. Knox (Lobeliaceae). These cloned fragments and a set of 106 clones spanning the tobacco chloroplast genome were used as probes to determine the cpDNA restriction fragment arrangement forSac I and six other restriction enzymes (BamH I,EcoR V,Hind III,Nci I,Pst I, andXho I) and the chloroplast genome arrangement ofL. thuliniana relative to tobacco, which has been fully sequenced and is collinear with the hypothesized ancestral genome arrangement of angiosperms. The results confirm and refine our previous understanding of the chloroplast genome arrangement in the large single-copy region (LSC) and reveal (1) a roughly 11 kilobase (kb) expansion of the inverted repeat (IR) into the small single-copy region (SSC) and (2) apparent sequence divergence of the DNA segment inL. thuliniana that corresponds to ORF1901 in tobacco. The expansion of the IR into the SSC is present in all other examined members ofLobeliaceae, Cyphiaceae, andCampanulaceae, which indicates that the IR expansion was an early event in the cpDNA evolution of theCampanulales. The IR expansion into the SSC was not present inSphenoclea, which additionally supports exclusion of this genus from theCampanulaceae.

  • The chloroplast genome arrangement ofLobelia thuliniana (Lobeliaceae): Expansion of the inverted repeat in an ancestor of theCampanulales
    Plant Systematics and Evolution, 1999
    Co-Authors: Eric B. Knox, Jeffrey D. Palmer
    Abstract:

    A clone-bank of Sac I restriction fragments was constructed from the chloroplast DNA (cpDNA) of Lobelia thuliniana E. B. Knox ( Lobeliaceae ). These cloned fragments and a set of 106 clones spanning the tobacco chloroplast genome were used as probes to determine the cpDNA restriction fragment arrangement for Sac I and six other restriction enzymes ( Bam H I, Eco R V, Hind III, Nci I, Pst I, and Xho I) and the chloroplast genome arrangement of L. thuliniana relative to tobacco, which has been fully sequenced and is collinear with the hypothesized ancestral genome arrangement of angiosperms. The results confirm and refine our previous understanding of the chloroplast genome arrangement in the large single-copy region (LSC) and reveal (1) a roughly 11 kilobase (kb) expansion of the inverted repeat (IR) into the small single-copy region (SSC) and (2) apparent sequence divergence of the DNA segment in L. thuliniana that corresponds to ORF1901 in tobacco. The expansion of the IR into the SSC is present in all other examined members of Lobeliaceae, Cyphiaceae , and Campanulaceae , which indicates that the IR expansion was an early event in the cpDNA evolution of the Campanulales. The IR expansion into the SSC was not present in Sphenoclea , which additionally supports exclusion of this genus from the Campanulaceae.

  • Monophyly of the Asteridae and Identification of Their Major Lineages Inferred From DNA Sequences of rbcL
    Annals of the Missouri Botanical Garden, 1992
    Co-Authors: Richard G. Olmstead, Helen J. Michaels, Kathy M. Scott, Jeffrey D. Palmer
    Abstract:

    A parsimony analysis of 57 angiosperm rbcL sequences was conducted to test the monophyly of the Asteridae and to identify major lineages within the Asteridae. Three major clades, the Caryophyllidae, the Rosidae plus Dilleniidae, and the Asteridae sensu lato, emerge from an unresolved radiation in the «higher» dicots. The Asteridae sens. lat. include the Ericales, Cornales, and Apiales in addition to the Asteridae sens. str. Two major lineages within the Asteridae sens. lat. are identified: the Dipsacales, Apiales, Asterales, and Campanulales in one, and the Gentianales, Scrophulariales, Lamiales, Boraginales, and Solanales in the other (...)

Thomas G. Lammers - One of the best experts on this subject based on the ideXlab platform.

  • Phylogenetic relationships in theCampanulales based onrbcL sequences
    Plant Systematics and Evolution, 1994
    Co-Authors: Mary E. Cosner, Robert K. Jansen, Thomas G. Lammers
    Abstract:

    Phylogenetic relationships within the angiosperm order Campanulales were investigated by comparative sequencing of the chloroplast gene rbcL. Complete rbcL sequences were obtained for ten species in six families within the order. These data were analyzed along with previously published rbcL sequences from other taxa (for a total of 117 species) within the subclass Asteridae and outgroups, producing 32 equally parsimonious trees. A subset consisting of 44 of these taxa was then chosen and more rigorous analyses performed, resulting in four equally parsimonious trees. Results indicate that two major clades roughly corresponding to traditionally circumscribed Asterales and Campanulales exist as sister taxa. In particular, the rbcL trees indicate that Sphenoclea is not a member of Campanulales or Asterales , that Pentaphragma is more closely allied to Asterales than Campanulales , that the Cyphiaceae are not monophyletic, that Campanulaceae and Lobeliaceae are not sister taxa, and that Stylidiaceae are correctly placed within Campanulales.

  • phylogenetic relationships in the Campanulales based on rbcl sequences
    Plant Systematics and Evolution, 1994
    Co-Authors: Mary E. Cosner, Robert K. Jansen, Thomas G. Lammers
    Abstract:

    Phylogenetic relationships within the angiosperm orderCampanulales were investigated by comparative sequencing of the chloroplast generbcL. CompleterbcL sequences were obtained for ten species in six families within the order. These data were analyzed along with previously publishedrbcL sequences from other taxa (for a total of 117 species) within the subclassAsteridae and outgroups, producing 32 equally parsimonious trees. A subset consisting of 44 of these taxa was then chosen and more rigorous analyses performed, resulting in four equally parsimonious trees. Results indicate that two major clades roughly corresponding to traditionally circumscribedAsterales andCampanulales exist as sister taxa. In particular, therbcL trees indicate thatSphenoclea is not a member ofCampanulales orAsterales, thatPentaphragma is more closely allied toAsterales thanCampanulales, that theCyphiaceae are not monophyletic, thatCampanulaceae andLobeliaceae are not sister taxa, and thatStylidiaceae are correctly placed withinCampanulales.

  • circumscription and phylogeny of the Campanulales
    Annals of the Missouri Botanical Garden, 1992
    Co-Authors: Thomas G. Lammers
    Abstract:

    Systematic relationships of the Campanulales were reexamined through the integration of data accumulated from morphological, anatomical, embryological, palynological, cytological, ultrastructural, chemical, molecular, and paleontological studies. Interpretation of these data suggests that the most natural circumscription of the order may be achieved by retaining Asteraceae and Calyceraceae, adding Menyanthaceae, removing Donatiaceae and Stylidiaceae to Ericales, and including Brunonia in Goodeniaceae rather than its own family. Phylogenies based on chloroplast DNA restriction fragment analysis and rbcL sequencing, supported by embryological and chemical data, suggest a basal dichotomy into two clades (...)

Eric B. Knox - One of the best experts on this subject based on the ideXlab platform.

  • The chloroplast genome arrangement ofLobelia thuliniana (Lobeliaceae): Expansion of the inverted repeat in an ancestor of theCampanulales
    Plant Systematics and Evolution, 1999
    Co-Authors: Eric B. Knox, Jeffrey D. Palmer
    Abstract:

    A clone-bank of Sac I restriction fragments was constructed from the chloroplast DNA (cpDNA) of Lobelia thuliniana E. B. Knox ( Lobeliaceae ). These cloned fragments and a set of 106 clones spanning the tobacco chloroplast genome were used as probes to determine the cpDNA restriction fragment arrangement for Sac I and six other restriction enzymes ( Bam H I, Eco R V, Hind III, Nci I, Pst I, and Xho I) and the chloroplast genome arrangement of L. thuliniana relative to tobacco, which has been fully sequenced and is collinear with the hypothesized ancestral genome arrangement of angiosperms. The results confirm and refine our previous understanding of the chloroplast genome arrangement in the large single-copy region (LSC) and reveal (1) a roughly 11 kilobase (kb) expansion of the inverted repeat (IR) into the small single-copy region (SSC) and (2) apparent sequence divergence of the DNA segment in L. thuliniana that corresponds to ORF1901 in tobacco. The expansion of the IR into the SSC is present in all other examined members of Lobeliaceae, Cyphiaceae , and Campanulaceae , which indicates that the IR expansion was an early event in the cpDNA evolution of the Campanulales. The IR expansion into the SSC was not present in Sphenoclea , which additionally supports exclusion of this genus from the Campanulaceae.

  • the chloroplast genome arrangement of lobelia thuliniana lobeliaceae expansion of the inverted repeat in an ancestor of the Campanulales
    Plant Systematics and Evolution, 1999
    Co-Authors: Eric B. Knox, Jeffrey D. Palmer
    Abstract:

    A clone-bank ofSac I restriction fragments was constructed from the chloroplast DNA (cpDNA) ofLobelia thulinianaE. B. Knox (Lobeliaceae). These cloned fragments and a set of 106 clones spanning the tobacco chloroplast genome were used as probes to determine the cpDNA restriction fragment arrangement forSac I and six other restriction enzymes (BamH I,EcoR V,Hind III,Nci I,Pst I, andXho I) and the chloroplast genome arrangement ofL. thuliniana relative to tobacco, which has been fully sequenced and is collinear with the hypothesized ancestral genome arrangement of angiosperms. The results confirm and refine our previous understanding of the chloroplast genome arrangement in the large single-copy region (LSC) and reveal (1) a roughly 11 kilobase (kb) expansion of the inverted repeat (IR) into the small single-copy region (SSC) and (2) apparent sequence divergence of the DNA segment inL. thuliniana that corresponds to ORF1901 in tobacco. The expansion of the IR into the SSC is present in all other examined members ofLobeliaceae, Cyphiaceae, andCampanulaceae, which indicates that the IR expansion was an early event in the cpDNA evolution of theCampanulales. The IR expansion into the SSC was not present inSphenoclea, which additionally supports exclusion of this genus from theCampanulaceae.