Consulta: creatorFacets:"Dessein, S."
Registros recuperados: 13
Data/hora: 03/06/2024 07:50:37

Palynological Characters and Their Phylogenetic Signal in Rubiaceae
Provedor de dados: 16
Autores: Dessein, S.; Ochoterena, H.; De Block, P.; Lens, F.; Robbrecht, E.; Schols, P.; Smets, E.; Vinckier, S.; Huysmans, S.
In the 1990s Rubiaceae became a hot spot for systematists, mainly due to the comprehensive treatment of the family by Robbrecht in 1988. Next to the exploration of macromolecular characters to infer the phylogeny, the palynology of Rubiaceae finally received the attention it deserves. This article aims to present a state-of-the-art analysis of the systematic palynology of the family. The range of variation in pollen morphology is wide, and some of the pollen features are not known from other angiosperm taxa; e.g., a looplike or spiral pattern for the position of apertures in pantoaperturate grains. We compiled an online database at the generic level for the major pollen characters and orbicule presence in Rubiaceae. An overview of the variation is...
Tipo: Article / Letter to the editor
Palavras-chave: Rubiaceae; Pollen morphology; Palynology; Phylogeny.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407298

Floral ontogeny of the Afro-Madagascan genus Mitrasacmopsis with comments on the development of superior ovaries in Rubiaceae
Provedor de dados: 16
Autores: Groeninckx, I.; Vrijdaghs, A.; Huysmans, S.; Smets, E.; Dessein, S.
Background and Aims Members of Rubiaceae are generally characterized by an inferior ovary. However, Mitrasacmopsis is cited in the literature as having a semi-inferior to superior ovary. It has previously been hypothesized that the gynoecial development of Rubiaceae with semi-inferior to superior ovaries takes place in the same way as in Gaertnera, one of the most commonly cited rubiaceous genera with a superior ovary. To test this hypothesis, a floral ontogenetic study of Mitrasacmopsis was carried out with special attention paid to the gynoecial development.    Methods Floral ontogeny and anatomy of Mitrasacmopsis were examined using scanning electron and light microscopy.    Key Results At an early developmental stage, a concavity becomes visible in the...
Tipo: Article / Letter to the editor
Palavras-chave: Mitrasacmopsis quadrivalvis; Gaertnera; Floral ontogeny; 42.48.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/422222

Woodiness within the Spermacoceae–Knoxieae alliance (Rubiaceae): retention of the basal woody condition in Rubiaceae or recent innovation?
Provedor de dados: 16
Autores: Lens, F.; Groeninkx, I.; Smets, E.; Dessein, S.
† Background and Aims The tribe Spermacoceae is essentially a herbaceous Rubiaceae lineage, except for some species that can be described as ‘woody’ herbs, small shrubs to treelets, or lianas. Its sister tribe Knoxieae contains a large number of herbaceous taxa, but the number of woody taxa is higher compared to Spermacoceae. The occurrence of herbaceous and woody species within the same group raises the question whether the woody taxa are derived from herbaceous taxa (i.e. secondary woodiness), or whether woodiness represents the ancestral state (i.e. primary woodiness). Microscopic observations of wood anatomy are combined with an independent molecular phylogeny to answer this question.  † Methods Observations of wood anatomy of 21 woody Spermacoceae and...
Tipo: Article / Letter to the editor
Palavras-chave: Knoxieae; LM; Primary woodiness; Rubiaceae; Rubioideae; Secondary woodiness; Spermacoceae; Wood anatomy; 42.56.
Ano: 2009
URL: http://www.repository.naturalis.nl/record/428974

A new species of Colletoecema (Rubiaceae) from southern Cameroon with a discussion of relationships among basal Rubioideae
Provedor de dados: 16
Autores: Sonké, B.; Dessein, S.; Taedoumg, H.; Groeninckx, I.; Robbrecht, E.
Colletoecema magna, a new species from the Ngovayang Massif (southern Cameroon) is described and illustrated. A comparative morphological study illustrates the similar placentation and fruit anatomy of the novelty and Colletoecema dewevrei, the only other species of the genus. Colletoecema magna essentially differs from C. dewevrei by its sessile flowers and fruits, the corolla tube that is densely hairy above the insertion point of the stamens and the anthers that are included. Further characters that separate the novelty are its larger leaves, more condensed inflorescences, and larger fruits. Its position within Colletoecema is corroborated by atpB-rbcL and rbcL chloroplast sequences. The relationships among the basal lineages of the subfamily...
Tipo: Article / Letter to the editor
Palavras-chave: Rubioideae; Rubiaceae; Colletoecema; Chloroplast DNA; Ngovayang massif.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/525494

Elaborate Petals in Australian Spermacoce (Rubiaceae) Species: Morphology, Ontogeny and Function
Provedor de dados: 16
Autores: Vaes, E.; Vrijdaghs, A.; Smets, E.; Dessein, S.
Background and Aims Australian Spermacoce species display various types of elaborate petals. Their precise morphology, ontogenetic origin, and function are hitherto unknown. The aim of the present paper is to unravel the development and nature of the diverse types of elaborate petals in Spermacoce through a floral ontogenetic study.    Methods The floral ontogeny of six species characterized by different types of corolla appendages was studied by scanning electron microscopy and light microscopy. In order to elucidate the possible functions of the elaborate petals, field observations were conducted as well.   Key Results Scanning electronmicrographs show that full-grown petals of Spermacoce lignosa, S. phaeosperma and S. redacta bear appendages on their...
Tipo: Article / Letter to the editor
Palavras-chave: Australia; Corolla appendages; Elaborate petals; Floral ontogeny; Pollination; Rubiaceae; Spermacoce brevidens; S. caudata; S. erectiloba; S. lignosa; S. phaeosperma; S. redacta.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/407325

The tribal placement of the monospecific tropical African genus Petitiocodon (Rubiaceae) based on molecular data and morphology
Provedor de dados: 16
Autores: Tosh, J.; Block, P. De; Davis, A.P.; Dessein, S.; Robbrecht, E.; Smets, E.F.
A first phylogenetic placement of Petitiocodon based on molecular sequence data from three plastid regions (accD-psa1, rpl16 and trnL-F) is presented, in conjunction with a reassessment of morphology for the genus. Our results do not support an evolutionary affinity between Petitiocodon and Tricalysia (Coffeeae) as suggested by previous studies, but they confirm other research that Petitiocodon and Didymosalpinx are distinct genera. Placement of Petitiocodon in tribe Octotropideae is well-supported on the basis of molecular data and floral and carpological characters.
Tipo: Article / Letter to the editor
Palavras-chave: Octotropideae; African flora; AccD-psa1; Rpl16; TrnL-F; Molecular phylogenetics; Placentation.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/525286

A New Heterophyllous Spermacoce Species (Rubiaceae) from the Marungu Highlands, Democratic Republic of the Congo
Provedor de dados: 16
Autores: Dessein, S.; Robbrecht, E.; Smets, E.
Spermacoce heteromorpha Dessein (Rubiaceae, Spermacoceae) is newly described and illustrated. It grows on the Marungu highlands of the Democratic Republic of the Congo (D.R. Congo) at altitudes of 1800 to 1900 m. The species resembles the Tanzanian Spermacoce taylorii Verdcourt, from which it mainly differs in having terminal inflorescences, only slightly exserted anthers, and densely pubescent stems. Moreover, Spermacoce heteromorpha features marked heterophylly, with long leaves at the plant’s base and much shorter cauline leaves, a type of heterophylly rarely observed in Spermacoce or in the Rubiaceae as a whole. The finding of this species exemplifies the unique floristic richness of this underexplored part of D.R. Congo.
Tipo: Article / Letter to the editor
Palavras-chave: Democratic Republic of the Congo; Heterophylly; Marungu highlands; Rubiaceae; Spermacoce.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/407334

Gomphocalyx and Phylohydrax (Rubiaceae): sister taxa excluded from Spermacoceae s.s., featuring a remarkable case of convergent evolution
Provedor de dados: 16
Autores: Dessein, S.; Andersson, L.; Geuten, K.; Smets, E.; Robbrecht, E.
The genera Gomphocalyx and Phylohydrax (Rubiaceae) have been invariably placed in the tribe Spermacoceae s.s. based on the uni-ovulate ovary locules and pluri-aperturate pollen grains. Sequence data from the rps16 intron and the rbcL gene here presented exclude Gomphocalyx and Phylohydrax from Spermacoceae s.s. The two genera are closely related and their nearest relatives are found among members of the former tribe Hedyotideae. This position may be surprising at first, because the growth form of Phylohydrax is similar to some observed in Spermacoceae s.s. A detailed survey of morphological and anatomical characters shows, however, that the character states of the two genera are largely consistent with the here-proposed position in Hedyotideae. The...
Tipo: Article / Letter to the editor
Palavras-chave: Convergent evolution; Gomphocalyx; Hydrophylax; Phylohydrax; Rubiaceae; Spermacoceae.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407302

Geophila erythrocarpa (Rubiaceae), a new species from D.R.Congo and Zambia
Provedor de dados: 16
Autores: Dessein, S.; Vanthournout, S.; Niyongabo, F.
The species Geophila erythrocarpa (Rubiaceae) is described and illustrated. The new species is restricted to dry, dense forests of the Katanga province in D.R.Congo and the adjoining Copperbelt province in Zambia. The species is similar to and in the herbarium easily confused with G. obvallata from which it most clearly differs in having red instead of blue or black fruits. In flowering state, the two species can be separated by differences in calyx morphology. The new species shares the red-coloured fruits with G. afzelii, but differs from this species in the undivided stipules, the fewer-flowered inflorescences with smaller bracts, and details of the leaf coloration. The new species is further compared with all other Geophila species reported from Zambia...
Tipo: Article / Letter to the editor
Palavras-chave: Copperbelt; D.R.Congo; Geophila; IUCN; Katanga; Rubiaceae; Zambia.
Ano: 2011
URL: http://www.repository.naturalis.nl/record/524943

Pollen of the Spermacoce (Rubiaceae) species from the Northern Territory of Australia: morphology and taxonomic significance
Provedor de dados: 16
Autores: Dessein, S.; Harwood, R.; Smets, E.; Robbrecht, E.
Complementary to the revision of the genus Spermacoce in the Northern Territory of Australia, pollen morphology of 48 of the 53 native Spermacoce species from the Northern Territory has been investigated by scanning electron and light microscopy. There is considerable variation for most diagnostic pollen characters. The average equatorial diameter (E) ranges from 10.5 to 41.7 Î¼m. Grains are invariably colporate with apertures situated at the equator (being zonocolporate). The number of apertures varies from 3 to 17. The endoaperture is generally an endocingulum, often with a secondary thinning at the ectocolpus; one species has endocolpi. The sexine is usually perforate, but psilate, foveolate, and (micro)reticulate patterns were also found. Supratectal...
Tipo: Article / Letter to the editor
Palavras-chave: Spermacoce; Rubiaceae; Pollen morphology; Palynology; Australia; Northern Territory.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407293

Hymenodictyeae (Rubiaceae – Cinchonoideae) and its phylogenetic significance
Provedor de dados: 16
Autores: Verellen, J.; Dessein, S.; Razafimandimbison, S.G.; Smets, E.; Huysmans, S.
The tribe Naucleeae has recently been recircumscribed on the basis of both morphological and molecular [rbcL, trnT-F, internal transcribed spacer (ITS)] evidence, and has been found to be the sister group of the tribe Hymenodictyeae Razafim. &amp; B. Bremer. In order to find pollen morphological support for this new classification, the pollen and orbicules of 65 species, representing 23 Naucleeae and the two Hymenodictyeae genera, were investigated by scanning electron and light microscopy. Naucleeae pollen is very small (&lt; 20 µm) to small (20–30 µm) and its shape in equatorial view is suboblate to spheroidal or, more rarely, subprolate. Three compound apertures are present, each comprising a long and narrow ectocolpus, a circular to slightly lolongate...
Tipo: Article / Letter to the editor
Palavras-chave: Compound apertures; Endoapertures; Orbicule morphology; Palynology; Sexine ornamentation; 42.48.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/422226

Palynological Variation in Balsaminoid Ericales. I. Marcgraviaceae
Provedor de dados: 16
Autores: Lens, F.; Dressler, S.; Vinckier, S.; Janssens, S.; Dessein, S.; Van Evelghem, L.; Smets, E.
Background and Aims Marcgraviaceae are a rather small family of seven genera and approx. 130 neotropical species. This study aims to present a detailed palynological survey of the family in order to comment on the intrafamily relationships and possible correlations with pollinators. Methods In total, 119 specimens representing 67 species and all genera are observed using light microscopy and scanning electron microscopy. Furthermore, eight species from five genera are studied with transmission electron microscopy.  Key Results Our results show that pollen grains of Marcgraviaceae are small (20–35 mm), have three equatorial apertures, granules on the colpus membrane, oblate spheroidal to prolate spheroidal shapes, mainly psilate to perforate ornamentations,...
Tipo: Article / Letter to the editor
Palavras-chave: Balsaminoids; Ericales; Marcgraviaceae; Neotropics; Orbicules; Palynology; SEM; TEM.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407283

The tribal placement of the monospecific tropical African genus Petitiocodon (Rubiaceae) based on molecular data and morphology
Provedor de dados: 16
Autores: Tosh, J.; De Block, P.; Davis, A.P.; Dessein, S.; Robbrecht, E.; Smets, E.
A first phylogenetic placement of Petitiocodon based on molecular sequence data from three plastid regions (accD-psa1, rpl16 and trnL-F) is presented, in conjunction with a reassessment of morphology for the genus. Our results do not support an evolutionary affinity between Petitiocodon and Tricalysia (Coffeeae) as suggested by previous studies, but they confirm other research that Petitiocodon and Didymosalpinx are distinct genera. Placement of Petitiocodon in tribe Octotropideae is well-supported on the basis of molecular data and floral and carpological characters.
Tipo: Article / Letter to the editor
Palavras-chave: Octotropideae; African flora; AccD-PSA1; Rpl16; TrnL-F; Molecular phylogenetics; Placentation; 42.58.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/449521