Consulta: creatorFacets:"Smets, E."
Registros recuperados: 59
Data/hora: 09/06/2024 18:15:06

A search for phylogenetically informative wood characters within Lecythidaceae s.l.
Provedor de dados: 16
Autores: Lens, F.; Baas, P.; Jansen, S.; Smets, E.
The wood structure of 71 species representing 24 genera of the pantropical Lecythidaceae s.l., including the edible Brazil nuts (Bertholletia excelsa) and the spectacular cannon-ball tree (Couroupita guianensis), was investigated using light and scanning electron microscopy. This study focused on finding phylogenetically informative characters to help elucidate any obscure evolutionary patterns within the family. The earliest diverging subfamily Napoleonaeoideae has mixed simple/scalariform vessel perforations, scalariform vessel-ray pitting, and high multiseriate rays, all features that are also present in Scytopetaloideae. The wood structure of Napoleonaea is distinct, but its supposed close relative Crateranthus strongly resembles Scytopetaloideae. The...
Tipo: Article / Letter to the editor
Palavras-chave: Ericales; Lecythidaceae s.l.; Lecythidaceae s.s.; Napoleonaeaceae; Scytopetalaceae; Systematic wood anatomy; 42.48.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/422216

Comparative wood anatomy of Andromedeae s.s., Gaultherieae, Lyonieae and Oxydendreae (Vaccinioideae, Ericaceae s.l.)
Provedor de dados: 16
Autores: Lens, F.; Smets, E.; Jansen, S.
The wood anatomical structure of 11 out of 13 genera from four tribes of the Vaccinioideae, namely Andromedeae s.s., Gaultherieae, Lyonieae and Oxydendreae (Ericaceae s.l.), is described using light and scanning electron microscopy. Several features of the secondary xylem support the tribal classification based on molecular data: arrangement of vessel-ray pitting, height of multiseriate rays and the shape of the body ray cells. Oxydendreae are clearly defined from the other representatives by various wood anatomical features. Gaultherieae can be distinguished from Lyonieae by differences in vessel perforation plates, vessel-ray pitting, height and structure of multiseriate rays, and occurrence of prismatic crystals, but the wood of Andromedeae s.s. is...
Tipo: Article / Letter to the editor
Palavras-chave: Comparative wood anatomy; Andromedeae; Gaultherieae; Lyonieae; Oxydendreae; Vaccinioideae; Ericaceae; Andromedeae sensu Stevens; Pith structure; 42.58.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/424620

Variation in xylem structure from tropics to tundra: Evidence from vestured pits
Provedor de dados: 16
Autores: Jansen, S.; Baas, P.; Gasson, P.; Lens, F.; Smets, E.
Bordered pits play an important role in permitting water flow among adjacent tracheary elements in flowering plants. Variation in the bordered pit structure is suggested to be adaptive in optimally balancing the conflict between hydraulic efficiency (conductivity) and safety from air entry at the pit membrane (air seeding). The possible function of vestured pits, which are bordered pits with protuberances from the secondary cell wall of the pit chamber, could be increased hydraulic resistance or minimized vulnerability to air seeding. These functional hypotheses have to be harmonized with the notion that the vestured or nonvestured nature of pits contains strong phylogenetic signals (i.e., often characterize large species-rich clades with broad ecological...
Tipo: Article / Letter to the editor
Palavras-chave: Xylem structure; Vestured pits; Scalariform perforation plates; Simple perforation plates; Hydraulic system; Drought stress; 42.42.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/423503

Isolepis levynsiana, a New Name for Cyperus tenellus (Cyperaceae)
Provedor de dados: 16
Autores: Muthama Muasya, A.; Simpson, D.A.; Smets, E.
The recently published name Isolepis tenella (L. f) Muasya &amp; D. A. Simpson is illegitimate, because there exists an earlier homonym. A new name, I. levynsiana Muasya &amp; D. A. Simpson, is proposed for Cyperus tenellus.
Tipo: Article / Letter to the editor
Palavras-chave: Cyperaceae; Cyperus; Isolepis; 42.48.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/422234

Pollen Evolution in Yams (Dioscorea: Dioscoreaceae)
Provedor de dados: 16
Autores: Schols, P.; Wilkin, P.; Furness, C.; Huysmans, S.; Smets, E.
Pollen character evolution in yams (Dioscorea: Dioscoreaceae) was investigated in relation to the phylogeny obtained from a recent combined analysis of rbcL and matK gene sequences. The following characters were evaluated: pollen size, aperture number, sexine ornamentation, perforation density, and orbicule presence or absence. Continuous characters were coded using the gap weighting method. Each character was optimized using MacClade onto a tree selected at random from analyses based on molecular data of Wilkin et al. The results indicate that in Dioscorea pollen size decreases in the more derived clades. The latter observation may be related to the evolution of annually replaced tubers. Aperture number increases from one in the monosulcate Stenophora...
Tipo: Article / Letter to the editor
Palavras-chave: Dioscorea; Dioscoreaceae; Pollen; Evolution; Phylogeny.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407309

Vessel grouping patterns in subfamilies Apocynoideae and Periplocoideae confirm phylogenetic value of wood structure within Apocynaceae
Provedor de dados: 16
Autores: Lens, F.; Endress, M.E.; Baas, P.; Jansen, S.; Smets, E.; , D.
This study contributes to our understanding of the phylogenetic signifi cance and major evolutionary trends in the wood of the dogbane family (Apocynaceae), one of the largest and economically most important angiosperm families. Based on LM and SEM observations of 56 Apocynoideae species — representing all currently recognized tribes — and eight Periplocoideae, we found striking differences in vessel grouping patterns (radial multiples vs. large clusters) between the mainly nonclimbing apocynoid tribes (Wrightieae, Malouetieae, Nerieae) and the climbing lineages (remaining Apocynoideae and Periplocoideae). The presence of large vessel clusters in combination with fibers in the ground tissue characterizing the climbing Apocynoideae and Periplocoideae...
Tipo: Article / Letter to the editor
Palavras-chave: Apocynaceae; Apocynoideae; APSA clade; Climbing vs. nonclimbing anatomy; Periplocoideae; Systematic wood anatomy; Tribal classification; 42.58.
Ano: 2009
URL: http://www.repository.naturalis.nl/record/424670

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

The Floral Scales in Hellmuthia (Cyperaceae, Cyperoideae) and Paramapania (Cyperaceae, Mapanioideae): An Ontogenetic Study
Provedor de dados: 16
Autores: Vrijdaghs, A.; Goetghebeur, P.; Smets, E.; Muasya, A.
Background and Aims In 1976 the monotypic genus Hellmuthia was placed in the Hypolytreae s.l., but was subsequently ascribed to the Mapanioideae, tribe Chrysitricheae, mainly because of the presence in Hellmuthia of two lateral, mapanioid-like floral scales with ciliated keels, the anatomy of the nutlet, the embryo and the inflorescence. Recently, based on cladistic analyses and supported by pollen ontogenetic evidence, Hellmuthia was transferred to a Cyperaceae, tribe Cypereae, clade mainly consisting of Ficinia and Isolepis. In this study, the floral ontogeny in Hellmuthia was investigated and compared with the floral ontogeny in Paramapania, with special attention for the floral scales.   Methods Freshly collected inflorescences of Hellmuthia...
Tipo: Article / Letter to the editor
Palavras-chave: Floral scales; Paramapania; Floral ontogeny; Cyperaceae; Hellmuthia; SEM; Homology.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/407327

A histological study of microsporogenesis in Tarenna gracilipes (Rubiaceae)
Provedor de dados: 16
Autores: Vinckier, S.; Smets, E.
We studied the microsporogenesis in Tarenna gracilipes (Hayata) Ohwi, with special attention to the mode of exine deposition and tapetum development. We based this research on light (LM), scanning electron (SEM) and transmission electron microscopic (TEM) observations of developing anthers of T. gracilipes, from the microspore mother cell stage towards anther dehiscence. Evidence is supplied that the microsporogenesis in T. gracilipes can be considered as simultaneous. Columellae, foot layer and tectum develop in a fibrillar matrix. Similar with earlier studies in Rubiaceae species, a single white line formed near the plasmalemma in the extra-apertural region. The developing endexine dilated into several white line centered lamellae at the apertures. An...
Tipo: Article / Letter to the editor
Palavras-chave: Tarenna gracilipes; Rubiaceae; Microsporogenesis; Exine deposition; Tapetum development; Histology; Light microscopy; Scanning.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407305

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

Relationships within balsaminoid Ericales: a wood anatomical approach
Provedor de dados: 16
Autores: Lens, F.; Dressler, S.; Jansen, S.; Van Evelghem, L.; Smets, E.
Wood samples of 49 specimens representing 31 species and 11 genera of woody balsaminoids, i.e., Balsaminaceae, Marcgraviaceae, Pellicieraceae, and Tetrameristaceae, were investigated using light microscopy and scanning electron microscopy. The wood structure of Marcgraviaceae, Pellicieraceae, and Tetrameristaceae is characterized by radial vessel multiples with simple perforation plates, alternate vessel pitting, apotracheal and paratracheal parenchyma, septate libriform fibers, and the presence of raphides in ray cells. Tetrameristaceae and Pellicieraceae are found to be closely related based on the occurrence of unilaterally compound vessel-ray pitting and multiseriate rays with long uniseriate ends. The narrow rays in Pelliciera are characteristic of...
Tipo: Article / Letter to the editor
Palavras-chave: Balsaminaceae; Balsaminoid clade; Ericales; Marcgraviaceae; Paedomorphism; Pellicieraceae; Tetrameristaceae; Wood anatomy; 42.40.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407273

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

The Micromorphology of Pit Membranes in Tracheary Elements of Ericales: New Records of Tori or Pseudo-tori?
Provedor de dados: 16
Autores: Rabaey, D.; Lens, F.; Smets, E.; Janssen, S.
Background and Aims Intervascular pit membranes were examined within Ericales to determine the distribution and structure of torus-like thickenings.   Methods Forty-nine species representing 12 families of the order Ericales were investigated using light, scanning and transmission electron microscopy. They were compared with four species of Oleaceae to determine the true nature of the thickenings.   Key Results Pit membranes with torus-like thickenings were observed in seven species of Ericaceae and were found to be amorphous, plasmodesmata-associated structures with an irregular distribution. These pseudo-tori show major differences compared with true tori with respect to their distribution and ultrastructure. Genuine tori, which are strongly correlated...
Tipo: Article / Letter to the editor
Palavras-chave: Ericaceae; Ericales; Oleaceae; Pit membrane; Plasmodesmata; Pseudo-torus; Torus; Tracheary elements.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/407321

Comparative wood anatomy of the blueberry tribe (Vaccinieae, Ericaceae s.l.)
Provedor de dados: 16
Autores: Lens, F.; Kron, K.A.; Luteyn, J.L.; Smets, E.; Jansen, S.
Wood samples of 111 Vaccinieae specimens (Vaccinioideae, Ericaceae s.l.) representing 98 species and 26 genera are investigated with light microscopy and scanning electron microscopy. The wood structure of Vaccinieae delivers taxonomically important characters that can be used to define some subclades within the tribe. The wood of the large polyphyletic genus Vaccinium strongly resembles non-vaccinioid members of the family, which are characterized by bordered vessel-ray pits and relatively narrow (2- to 4-seriate) and low multiseriate rays (often less than 1000 mm) with exclusively or mainly procumbent body ray cells. The East Malesian clade, Meso-American/Caribbean clade, and the Andean clade show a combination of wood anatomical features that is lacking...
Tipo: Article / Letter to the editor
Palavras-chave: Blueberries; Comparative wood anatomy; Ericaceae; Neotropics; Secretory ducts; Systematics; Vaccinieae; 42.56.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/423810

Ecological trends in the wood anatomy of Vaccinioideae (Ericaceae s.l.)
Provedor de dados: 16
Autores: Lens, F.; Luteyn, J.L.; Smets, E.; Jansen, S.
The ecological wood anatomy of 128 vaccinioid wood samples (including 115 species, 35 genera), collected between 39°S and 60°N latitude and 10 m to 3400 m altitude is studied. Several wood anatomical features within the subfamily, viz. tangential vessel diameter, average length of tracheary elements, height of multiseriate rays, and presence of prismatic crystals are negatively correlated with increasing latitude, while vessel density and helical thickenings show a positive correlation with increasing latitude. Similar latitudinal trends are found within the genus Vaccinium (31 species studied). The correlation between various wood anatomical features and latitude is surprisingly high despite the fact that most tropical species grow in montane regions,...
Tipo: Article / Letter to the editor
Palavras-chave: Altitude; Ecological and functional wood anatomy; Ericaceae; Latitude; Vaccinioideae; Vaccinium; 42.58.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/424624

The phylogenetic significance of vestured pits in Boraginaceae
Provedor de dados: 16
Autores: Rabaey, D.; Lens, F.; Smets, E.; Jansen, S.
The bordered pit structure in tracheary elements of 105 Boraginaceae species is studied using scanning electron microscopy to examine the systematic distribution of vestured pits. Forty-three species out of 16 genera show a uniform presence of this feature throughout their secondary xylem. Most vestures are small, unbranched and associated with the outer pit aperture of bordered intervessel pits. The feature is likely to have originated independently in the distantly related subfamilies Boraginoideae (tribe Lithospermeae) and Ehretioideae. The distribution of vestures in Ehretia agrees with recent molecular phylogenies: (1) species with vestured pits characterise the Ehretia I group (incl. Rotula), and (2) species with non-vestured pits belong to the...
Tipo: Article / Letter to the editor
Palavras-chave: Boraginaceae; Boraginoideae; Bordered pit; Ehretioideae; Scanning electron microscopy; Vestures; 42.56.
Ano: 2010
URL: http://www.repository.naturalis.nl/record/430079

Comparative Pollen Development in Dioscoreales
Provedor de dados: 16
Autores: Schols, P.; Furness, C.; Merckx, V.; Wilkin, P.; Smets, E.
Pollen and orbicule ontogeny in representatives of three genera of Dioscoreales—Narthecium ossifragum Huds. (Nartheciaceae), Tacca artocarpifolia Seem. and Tacca chantrieri Andre´ (Dioscoreaceae), and Dioscorea communis (L.) Caddick &amp; Wilkin (Dioscoreaceae)—is described and illustrated using LM, SEM, and TEM. The main difference is in microsporogenesis, which is successive in Narthecium Huds. and simultaneous in Tacca J.R. &amp; G. Forst. and Dioscorea L. This is reflected in the tetrad configuration but not in the apertures: Narthecium and Tacca are monosulcate, while Dioscorea has two equatorial apertures. Other features of pollen development are similar in all three genera. Exine development starts at the proximal pole, and during the tetrad stage,...
Tipo: Article / Letter to the editor
Palavras-chave: Intine; Microsporogenesis; Monocotyledons; Orbicules; Pollen ontogeny; Systematics; Tapetum; Tetrads.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407299

Phylogenetic utility of the AP3/DEF K-domain and its molecular evolution in Impatiens (Balsaminaceae)
Provedor de dados: 16
Autores: Janssens, S.; Geuten, K.; Viaene, T.; Yong-Ming, Y.; Yi, S.; Smets, E.
APETALA3 (AP3)/DEFICIENS (DEF) is a MADS-box transcription factor that is involved in establishing the identity of petal and stamen floral organs. The AP3/DEF gene lineage has been extensively examined throughout the angiosperms in order to better understand its role in floral diversity and evolution. As a result, a large number of cloned AP3/DEF orthologues are available, which can be used for the design of taxon specific primers for phylogeny reconstruction of close relatives of the group of interest. Following this reasoning, we investigated the phylogenetic utility of the two AP3/DEF paralogues (ImpDEF1 and ImpDEF2) that were recently identified in the genus Impatiens (Balsaminaceae). K-domain introns 4 and 5 of both AP3/DEF duplicates were amplified...
Tipo: Article / Letter to the editor
Palavras-chave: APETALA3/DEFICIENS; Gene duplication; Impatiens; ImpDEF1; ImpDEF2; K-domain; Phylogenetic utility; 42.48.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/422232

The manifold characters of orbicules: structural diversity, systematic significance, and vectors for allergens
Provedor de dados: 16
Autores: Vinckier, S.; Cadot, P.; Smets, E.
In the anthers of flowering plants, gymnosperms, and seed ferns, tiny (¡1 mm) granules might occur on the radial and innermost tangential wall of secretory tapetum cells. These sporopollenin granules develop simultaneously with the pollen exine and are called orbicules or Ubisch bodies. The present paper focuses on two quite different topics associated with orbicules. The morphological and ultrastructural diversity of orbicules in the order Gentianales is summarized, and it is demonstrated that orbicules are a plesiomorphic feature in the order. Furthermore, orbicule characters seemed to be correlated with evolutionary trends in pollen dispersal unit and tapetum type features. In the second part, we report on our investigation of Corylus avellana L....
Tipo: Article / Letter to the editor
Palavras-chave: Orbicules; Morphology; Diversity; Gentianales; Plesiomorphic feature; Pollen; Corylus avellana L.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407306

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

Phylogenetics of Impatiens and Hydrocera (Balsaminaceae) using chloroplast atpB-rbcL spacer sequences
Provedor de dados: 16
Autores: Janssens, S.; Geuten, K.; Yuan, Y.; Song, Y.; Küpfer, P.; Smets, E.
Balsaminaceae are a morphologically diverse family with ca. 1,000 representatives that are mainly distributed in the Old World tropics and subtropics. To understand the relationships of its members, we obtained chloroplast atpB-rbcL sequences from 86 species of Balsaminaceae and five outgroups. Phylogenetic reconstructions using parsimony and Bayesian approaches provide a well-resolved phylogeny in which the sister group relationship between Impatiens and Hydrocera is confirmed. The overall topology of Impatiens is strongly supported and is geographically structured. Impatiens likely originated in South China from which it colonized the adjacent regions and afterwards dispersed into North America, Africa, India, the Southeast Asian peninsula, and the...
Tipo: Article / Letter to the editor
Palavras-chave: Balsaminaceae; Phylogeny; Reconstruction; Sister group relationship; Impatiens; Hydrocera.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/407352

Contributions to the Wood Anatomy of the Rubioideae (Rubiaceae)
Provedor de dados: 16
Autores: Jansen, S.; Lens, F.; Ntore, S.; Piesschaert, F.; Robbrechf, E.; Smets, E.
The secondary xylem of Craterispermeae, Coussareeae, Morindeae s.str., Prismatomerideae, Pauridiantheae, Urophylleae, and Triainolepideae (Rubiaceae, Rubioideae) is described and illustrated in detail. Genera that were previously placed in the Morindeae or Psychotrieae such as Damnacanthus, Lasianthus, Saldinia, and Trichosfachys are also included. Wood anatomical characters are compared with recent phylogenetic insights into the study group on the basis of molecular data. The observations demonstrate that the delimitation and separation of several taxa from the former Coussareeae/Morindeae/Prismatomerideae/Psychotrieae aggregate is supported by wood anatomical data. The Coussareeae can be distinguished from the other Rubioideae by their scanty parenchyma,...
Tipo: Article / Letter to the editor
Palavras-chave: Rubiaceae; Rubioideae; Systematic wood anatomy; 42.58.
Ano: 2001
URL: http://www.repository.naturalis.nl/record/421859

A comparative ultrastructural study of pit membranes with plasmodesmata associated thickenings in four angiosperm species
Provedor de dados: 16
Autores: Rabaey, D.; Lens, F.; Huysmans, S.; Smets, E.; Jansen, S.
Recent micromorphological observations of angiosperm pit membranes have extended the number and range of taxa with pseudo-tori in tracheary elements. This study investigates at ultrastructural level (TEM) the development of pseudo-tori in the unrelated Malus yunnanensis, Ligustrum vulgare, Pittosporum tenuifolium, and Vaccinium myrtillus in order to determine whether these plasmodesmata associated thickenings have a similar developmental pattern across flowering plants. At early ontogenetic stages, the formation of a primary thickening was observed, resulting from swelling of the pit membrane in fibre-tracheids and vesselelements. Since plasmodesmata appear to be frequently, but not always, associated with these primary pit membrane thickenings, it remains...
Tipo: Article / Letter to the editor
Palavras-chave: Ontogeny; Pseudo-torus; Tracheary element; Pit membrane; Bordered pit; Wood ultrastructure; 42.56.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/430078

Phylogeny and evolution of Burmanniaceae (Dioscoreales) based on nuclear and mitochondrial data
Provedor de dados: 16
Autores: Merckx, V.; Schols, P.; Maas - Van de Kamer, H.; Maas, P.; Huymans, S.; Smets, E.
The mycoheterotrophic Burmanniaceae are one of the three families currently recognized in the order Dioscoreales. Phylogenetic inference using nucleotide sequences of the nuclear 18S rDNA region and the mitochondrial nad1 b-c intron revealed two well-supported, major lineages within the family, corresponding to the two tribes recognized in the family: Burmannieae and Thismieae. All data supported a strong relationship between Thismieae and Tacca (Dioscoreaceae) making both Burmanniaceae and Dioscoreaceae polyphyletic. The three largest Burmanniaceae genera, Burmannia, Gymnosiphon, and Thismia, are paraphyletic. The splitting of Burmanniaceae into Burmannieae and Thismieae indicates two independent origins of mycoheterotrophy and correlated loss of...
Tipo: Article / Letter to the editor
Palavras-chave: 18S rDNA; Burmanniaceae; Dioscoreales; Molecular phylogeny; Mycoheterotrophy; Nad1 b-c intron; Thismiaceae; 42.48.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/422338

Petaloidy and petal identity MADS-box genes in the balsaminoid genera Impatiens and Marcgravia
Provedor de dados: 16
Autores: Geuten, K.; Becker, A.; Kaufmann, K.; Caris, P.; Janssens, S.; Viaene, T.; Theißen, G.; Smets, E.
Impatiens and Marcgravia have striking morphological innovations associated with the flowers. One of the sepals in Impatiens is spurred and petaloid, while in Marcgravia the petals are fused into a cap and nectary cups are associated with the inflorescence. Balsaminaceae (Impatiens) and Marcgraviaceae have surprisingly been shown to be closely related, since both belong to the balsaminoid clade of Ericales (basal asterids). However, several thorough morphological studies thus far have not revealed shared derived characters (synapomorphies) that support a close relationship between these families. In the balsaminoid clade, transitions from entirely green flowers to flowers with heterotopic petaloid organs can be observed. The primary role of class B genes...
Tipo: Article / Letter to the editor
Palavras-chave: SEPALLATA3; Class B genes; Petal identity; MADS-box genes; Impatiens; Marcgravia.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/407348

Wood anatomy of  Rauvolfioideae (Apocynaceae): a search for meaningful non-DNA characters at the tribal level
Provedor de dados: 16
Autores: Lens, F.; Endress, M.E.; Baas, P.; Jansen, S.; Smets, E.
Wood anatomical studies in the economically important Apocynaceae or dogbane family are fragmentary. This study represents a first attempt to unravel the phylogenetic signifi cance and major evolutionary trends in the wood of the family, using existing and new microscopic wood observations within the large subfamily Rauvolfi oideae. On the basis of LM and SEM observations of 91 species representing all 10 currently recognized tribes, we found that most of the tribes are characterized by a unique combination of wood characters, such as vessel grouping, vessel element length, fi ber type, frequency of uniseriate rays, and fused multiseriate rays. Climbing rauvolfi oid taxa can generally be distinguished from erect species by their wider vessels, tendency to...
Tipo: Article / Letter to the editor
Palavras-chave: Apocynaceae; APSA clade; Climbing vs. nonclimbing habit; Rauvolfi oideae; Systematic wood anatomy; Tribal classification; 42.58.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/424647

Isolepis tenella, a New Combination in Cyperaceae
Provedor de dados: 16
Autores: Muthama Muasya, A.; Simpson, D.; Smets, E.
Since the publication of a monograph on Isolepis (Cyperaceae) in 2002, further data on the genus have been collected, necessitating additional nomenclatural change. Isolepis is a predominantly southern hemisphere genus with high species diversity in South Africa and Australia. A new combination is made here: Isolepis tenella (L.f.) Muasya &amp; D. A. Simpson, transferring an aberrant annual previously named Cyperus tenellus.
Tipo: Article / Letter to the editor
Palavras-chave: Cyperaceae; Cyperus tenellus; Isolepis tenella.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/407339

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

Floral development in three species of Impatiens (Balsaminaceae)
Provedor de dados: 16
Autores: Caris, P.L.; Geuten, K.P.; Janssens, S.B.; Smets, E.
The floral morphological and developmental patterns in three species of Impatiens (Balsaminaceae), namely I. columbaria, I. hawkeri, and I. niamniamensis, were studied to contribute to a better understanding of floral evolution in the genus. Strangely enough, the highly diverse floral morphology and ontogeny of this horticulturally important genus have never been studied thoroughly (e.g., using scanning electron microscopic techniques). We discuss the position and the developmental sequence of the different perianth members. We hypothesized that in the course of evolution, the anterolateral sepals become reduced and that a morphocline can be recognized going from species with five sepals, over species with rudimentary sepals that fuse postgenitally with...
Tipo: Article / Letter to the editor
Palavras-chave: Balsaminaceae; Ericales; Floral development; Floral evolution; Floral morphology; Impatiens; Scanning electron microscopy; 42.40.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/422332

Stem anatomy supports Arabidopsis thaliana as a model for insular woodiness
Provedor de dados: 16
Autores: Lens, F.; Smets, E.; Melzer, S.
The soc1 ful double mutant of A. thaliana produced substantial secondary growth throughout all aboveground stems, whereas in the Col accession only a few cell layers of wood were produced at the base of old stems. This increased wood formation may be linked to inactivation of the flowering time genes SOC1 and FUL (Melzer et al., 2008). These two genes could play a crucial regulatory role in triggering genetic mechanisms that lead to insular woodiness outside A. thaliana, and this ‘simple’ two-gene loss could explain why many nonrelated herbaceous families have independently evolved into woody insular lineages throughout the world. However, SOC1 and FUL might not be the only suppressors of cambium formation; other upstream, downstream or parallel-acting...
Tipo: Article / Letter to the editor
Palavras-chave: Stem anatomy; Arabidopsis thaliana; Insular woodiness; Brassicaceae; Wood formation; 42.56.
Ano: 2012
URL: http://www.repository.naturalis.nl/record/429528

A Plastid Gene Phylogeny of the Yam Genus, Dioscorea: Roots, Fruits and Madagascar
Provedor de dados: 16
Autores: Wilkin, P.; Schols, P.; Chase, M.; Chayamarit, K.; Furness, C.; Huysmans, S.; Rakotonasolo, F.; Smets, E.; Thapyai, C.
Following recent phylogenetic studies of the families and genera of Dioscoreales, the identification of monophyletic infrageneric taxa in the pantropical genus Dioscorea is a priority. A phylogenetic analysis based on sequence data from the plastid genes rbcL and matK is presented, using 67 species of Dioscorea and covering all the main Old World and selected New World lineages. The analysis used 14 outgroup taxa, including Trichopus Gaertn., Tacca J.R. &amp; G. Forster, Stenomeris Planch., Burmannia L. and Thismia Griff. The main findings are: a) that a clade of rhizomatous taxa is sister to the rest of Dioscorea; b) the main Old World groups (such as the right-twining D. sect. Enantiophyllum) are monophyletic and c) there are two distinct lineages among...
Tipo: Article / Letter to the editor
Palavras-chave: Dioscorea; Phylogeny; Classification; Analysis; Plastid genes; RbcL; MatK; Character evolution.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407311

Micromorphology and systematic distribution of pit membrane thickenings in Oleaceae: Tori and pseudo-tori
Provedor de dados: 16
Autores: Rabaey, D.; Huysmans, S.; Lens, F.; Smets, E.; Jansen, S.
Recent studies on the functional significance of pit membranes in water conducting cells have renewed general interest in their micromorphology. At least two types of pit membrane thickenings have been described in angiosperm families, i.e. genuine tori and pseudo-tori. This study explores the distribution and morphology of pit membrane thickenings in 69 species and 23 genera within Oleaceae using light and electron microscopy. Torus-bearing pit membranes are confirmed for Osmanthus, and new records are reported for Chionanthus retusa, Picconia azorica, and P. excelsa, but not for the other species studied of Chionanthus. This infrageneric variation suggests that tori represent a plastic feature that has evolved more than once within the family as the...
Tipo: Article / Letter to the editor
Palavras-chave: Electron microscopy; Pit aperture; Pit membrane; Plasmodesmata; Pseudo-torus; Torus; Tracheid; Vessel element; 42.56.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/429536

The wood anatomy of the polyphyletic Icacinaceae s.l., and their relationships within asterids
Provedor de dados: 16
Autores: Lens, F.; Kårehed, J.; Baas, P.; Jansen, S.; Rabaey, D.; Huysmans, S.; Hamann, T.; Smets, E.
Wood samples from 53 species belonging to 41 genera of the Icacinaceae s.l. are investigated using light and scanning electron microscopy. The traditionally circumscribed Icacinaceae fall apart into four segregate families that are clearly nested within asterids, i.e., Icacinaceae s.str. (near or in Garryales), Cardiopteridaceae and Stemonuraceae (both Aquifoliales), and Pennantiaceae (Apiales). From a wood anatomical point of view, these families cannot easily be distinguished from each other. However, some features such as vessel distribution, perforation plate morphology, size and arrangement of vessel pits, fibre wall thickness, and the occurrence of cambial variants can be used to assign various species to one of the four families. The wood structure...
Tipo: Article / Letter to the editor
Palavras-chave: Cambial variants; Comparative wood anatomy; Garryales; Icacinaceae; LM; Oncotheca; SEM; 42.58.
Ano: 2008
URL: http://www.repository.naturalis.nl/record/424648

The Schoenus spikelet: a Rhipidium? A floral ontogenetic answer
Provedor de dados: 16
Autores: Vrijdaghs, A.; Goetghebeur, P.; Smets, E.; Caris, P.
The inflorescence unit of Schoenus nigricans and S. ferrugineus consists of a zigzag axis and distichously arranged bracts, each of which may or may not subtend a bisexual flower. Each flower seems to terminate a lateral axis. These features have led to a controversy about the nature of the inflorescence unit, particularly whether it is monopodial or sympodial. It was often seen as a pseudospikelet composed of a succession of lateral axes, each subtended by the prophyll of the previous axis, as in a rhipidium. Many authors, however, consider the inflorescence units of all Cyperaceae to be indeterminate, racemose, actual spikelets. In our study, we present new SEM observations on the floral ontogeny of S. nigricans, corroborating a monopodial interpretation...
Tipo: Article / Letter to the editor
Palavras-chave: Floral ontogeny; Monopodial; Rhipidium; Schoenus nigricans; SEM; Spikelet; 42.48.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/414074

Evolution of fruit and seed characters in the Diervilla and Lonicera clades (Caprifoliaceae, Dipsacales)
Provedor de dados: 16
Autores: Jacobs, B.; Lens, F.; Smets, E.
Background and Aims: The Diervilla and Lonicera clades are members of the family Caprifoliaceae (Dipsacales sensu Donoghue et al., 2001, Harvard Papers in Botany 6: 459–479). So far, the intergeneric relationships of the Lonicera clade and the systematic position of Heptacodium remain equivocal. By studying fruit and seed morphology and anatomy, an attempt is made to clarify these issues. In addition, this study deals with the evolution of fruit and seed characters of the Diervilla and Lonicera clades with reference to allied taxa.  Methods: Light and scanning electron microscopy were used for the morphological and anatomical investigations. Phylogenetic analyses were carried out by applying the parsimony and Bayesian inference optimality criteria....
Tipo: Article / Letter to the editor
Palavras-chave: Diervilla; Weigela; Symphoricarpos; Lonicera; Triosteum; Leycesteria; Heptacodium; Caprifoliaceae; Dipsacales; Fruit; Seed; Evolution; 42.56.
Ano: 2009
URL: http://www.repository.naturalis.nl/record/421854

The role of wood anatomy in phylogeny reconstruction of Ericales
Provedor de dados: 16
Autores: Lens, F.; Schönenberger, J.; Baas, P.; Jansen, S.; Smets, E.
The systematic significance of wood anatomical characters within Ericales is evaluated using separate and combined parsimony analyses including 23 wood characters and 3945 informative molecular characters. Analyses of wood features alone result in poorly resolved and conflicting topologies. However, when pedomorphic character states are coded as inapplicable, the combined bootstrap topology results in an increase of resolution and support at most deeper nodes compared with the molecular analyses. This suggests that phylogenetic information from the limited number of morphological characters is not completely swamped by an overwhelming amount of molecular data. Based on the morphology of vessels and fibers, and the distribution of axial parenchyma, two...
Tipo: Article / Letter to the editor
Palavras-chave: Anatomy; Phylogeny; Ericales; 42.48.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/422235

Floral ontogeny of Cneorum tricoccon L. (Rutaceae)
Provedor de dados: 16
Autores: Caris, P.; Smets, E.; De Coster, K.; Ronse De Craene, L.
The floral ontogeny of the Spurge olive (Cneorum tricoccon L.) is studied by means of scanning electron microscopic observations. Special attention is paid to the sequence of initiation of the floral parts, the occurrence of septal cavities, and the development of the nectariferous tissue. The nectary disc arises as a receptacular outgrowth below the ovary and independently from stamen development. By the extensive growth of this voluminous androgynophore, stamen filaments become enclosed by nectary tissue and as a result, they are seated in pits between the lobes of the disc. Between ovary and style, three lobes are present, which are covered with stomata – their function is unknown. The significance of the unusual trimery of the flower is discussed....
Tipo: Article / Letter to the editor
Palavras-chave: Androgynophore; Cneoraceae; Cneorum tricoccon L.; Floral ontogeny; Nectary; Rutaceae; Spurge olive.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/407345

Orbicules do not significantly contribute to the allergenic micro-aerosol emitted from birch trees
Provedor de dados: 16
Autores: Vinckier, S.; Cadot, P.; Grote, M.; Ceuppens, J.L.; Smets, E.
Tipo: Article / Letter to the editor
Palavras-chave: Betula verrucosa 1; Betula verrucosa 7; Immunogold electron microscopy; Pollen; Ubisch bodies; 42.40.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/422330

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

Wood anatomy of the Vanguerieae (Ixoroideae - Rubiaceae), with special emphasis on some geofrutices
Provedor de dados: 16
Autores: Lens, F.; Jansen, S.; Robbrecht, E.; Smets, E.
The Vanguerieae is a tribe consisting of about 500 species ordered in 27 genera. Although this tribe is mainly represented in Africa and Madagascar, Vanguerieae also occur in tropical Asia, Australia, and the isles of the Pacific Ocean. This study gives a detailed wood anatomical description of 34 species of 15 genera based on LM and SEM observations. The secondary xylem is homogeneous throughout the tribe and fits well into the Ixoroideae s.l. on the basis of fibre-tracheids and diffuse to diffuse-in-aggregates axial parenchyma. The Vanguerieae include numerous geofrutices that are characterised by massive woody branched or unbranched underground parts and slightly ramified unbranched aboveground twigs. The underground structures of geofrutices are not...
Tipo: Article / Letter to the editor
Palavras-chave: Vanguereae; Rubiaceae; Systematic wood anatomy; Geofrutex; 42.58.
Ano: 2000
URL: http://www.repository.naturalis.nl/record/423793

Are the genera Hallea and Mitragyna (Rubiaceae-Coptosapelteae) pollen morphologically distinct?
Provedor de dados: 16
Autores: Huysmans, S.; Robbrecht, E.; Smets, E.
Recent literature is controversial as regards the segregation of Hallea and Mitragyna, and pretends that the two genera show pollen morphological differences. In the present study the pollen morphology of all ten species of the complex is described on the basis of light and scanning electron microscopy (including examination of broken grains, which were obtained with a technique never applied in palynology, viz. shaking with glass beads). The two genera have 3-zonocolporate grains with compound apertures (endoapertures are always H-shaped, sometimes incompletely so). While Hallea showed to be stenopalynous (sexine always tectate-perforate), Mitragyna is more variable (sexine microreticulate or tectate-perforate), and several of its species have pollen...
Tipo: Article / Letter to the editor
Ano: 1994
URL: http://www.repository.naturalis.nl/record/524503

Pollen morphological variation in Vanguerieae (Ixoroideae - Rubiaceae)
Provedor de dados: 16
Autores: Lens, F.; Jansen, S.; Huysmans, S.; Robbrecht, E.; Smets, E.
The Vanguerieae is a large tribe of the subfamily Ixoroideae (Rubiaceae) and consists of about 500 species in 27 genera. This study gives a detailed pollen morphological description of 30 species from 16 genera, based on light microscopy and scanning electron microscopy. The Vanguerieae are considered to be stenopalynous, although there is some evidence to question this. First, there is a difference in sexine types that clearly de® nes Keetia and Psydrax ( both reticulate) , and Canthium and Vanguerieae (both perforate with very small perforations) from the other Vanguerieae investigated. Second, pollen grains corroborate the subgeneric delimitations of Canthium sensu Bridson. Pollen morphologically the tribe is characterised by ( 1) the shape of the...
Tipo: Article / Letter to the editor
Palavras-chave: Vanguereae; Ixoroideae; Rubiaceae; Pollen; Morphological variation; Stenopalynous; 42.58.
Ano: 2000
URL: http://www.repository.naturalis.nl/record/423771

Intervascular pit membranes with a torus in the wood of Ulmus (Ulmaceae) and related genera
Provedor de dados: 16
Autores: Jansen, S.; Choat, B.; Vinckier, S.; Lens, F.; Schols, P.; Smets, E.
• The distribution of intervascular pit membranes with a torus was investigated in juvenile wood samples of 19 species of Ulmus and seven related genera.  • A staining solution of safranin and alcian blue (35 : 65) was recommended to distinguish torus-bearing pit membranes using light microscopy.  • Intervascular pit membranes connecting relatively wide vessel elements resembled those of most angiosperms, as they were of uniform thickness. By contrast, bordered pit pairs with round to oval pit apertures and indistinct pit canals that connected narrow (incomplete) vessel elements or vascular tracheids with distinct helical thickenings were frequently characterized by a torus in ring-porous wood samples of Ulmus and Zelkova. Tori were lacking in...
Tipo: Article / Letter to the editor
Palavras-chave: Ulmus (elm); Ulmaceae; Pit membrane; Torus; Pit structure; Wood anatomy; Tracheary elements; 42.58.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/423388

Phylogeny of Cyperaceae based on DNA sequence data - a new rbcL analysis
Provedor de dados: 16
Autores: Simpson, D.A.; Muthama Muasya, A.; Alves, M.V.; Bruhl, J.J.; Dhooge, S.; Chase, M.W.; Furness, C.A.; Ghamkhar, K.; Goetghebeur, P.; Hodkinson, T.D.; Marchant, A.D.; Reznicek, A.A.; Nieuwborg, R.; Roalson, E.H.; Smets, E.; Starr, J.R.; Thomas, W.W.; Wilson, K.L.; Zhang, X.
Since the Monocots II meeting in 1998, significant new data have been published that enhance our systematic knowledge of Cyperaceae. Phylogenetic studies in the family have also progressed steadily. For this study, a parsimony analysis was carried out using all rbcL sequences currently available for Cyperaceae, including data for two new genera. One of the four subfamilies (Caricoideae) and seven of the 14 tribes (Bisboeckelereae, Cariceae, Cryptangieae, Dulichieae, Eleocharideae, Sclerieae, Trilepideae) are monophyletic. Subfamily Mapanioideae and tribe Chrysitricheae are monophyletic if, as the evidence suggests, Hellmuthia is considered a member of Cypereae. Some other features of our analysis include: well-supported Trilepideae and...
Tipo: Article / Letter to the editor
Palavras-chave: Cyperaceae; Monocotyledons; Phylogeny; RbcL; Sequence; 42.48.
Ano: 2007
URL: http://www.repository.naturalis.nl/record/414071

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

Insular woodiness on the Canary Islands: a remarkable case of convergent evolution
Provedor de dados: 16
Autores: Lens, F.; Davin, N.; Smets, E.; Arco, M. del.
Premise of research.   One of the most conspicuous aspects of island floras is the relatively high proportion of woody species. Often, but not always, these woody species have developed wood on the islands and have evolved from herbaceous continental ancestors, a phenomenon known as insular woodiness. Shifts from herbaceousness toward increased woodiness also occur on continents (the broader term “secondary woodiness” is more appropriate here and includes insular woodiness), but comprehensive worldwide knowledge about secondary woodiness within angiosperms remains lacking. We update hypotheses regarding the herbaceous ancestry of woody Canarian lineages in a molecular phylogenetic context and investigate the possible link of secondary woodiness and...
Tipo: Article / Letter to the editor
Palavras-chave: Canary Islands convergent evolution insular woodiness molecular phylogeny protracted juvenilism seconday woodinessq wood anatomy 42.21; 42.44.
Ano: 2013
URL: http://www.repository.naturalis.nl/record/453855

What shapes amino acid and sugar composition in Mediterranean floral nectars?
Provedor de dados: 16
Autores: Petanidou, T.; Van Laere, A.; Ellis, W.; Smets, E.
We studied the amino acid (AA) composition of the floral nectars of 73 plant species occurring in a phryganic (East Mediterranean garrigue) community and investigated whether AA and sugar composition is shaped by evolutionary (plant phylogeny), ecological (flowering time as a direct effect of summer drought) and coevolutionary (pollinator partnership) constraints. Our study utilised an extensive plantpollinator matrix compiled in the same area where the plants had been sampled.  Using HPLC we detected 22 AA compounds/groups of compounds, out of which 15 were commonly present in almost all nectars. Among all AAs, phenylalanine was the most abundant, especially in keystone (â€˜â€˜cornucopianâ€™â€™) plant species visited by many insect species, such as the...
Tipo: Article / Letter to the editor
Palavras-chave: Floral nectar; Composition; Mediterranean; Evolution; Ecology; Coeveloution.
Ano: 2006
URL: http://www.repository.naturalis.nl/record/407342

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

Description of 11 new Astiella (Spermacoceae, Rubiaceae) species endemic to Madagascar
Provedor de dados: 16
Autores: Groeninckx, I.; Janssens, S.; Smets, E.; Verstraete, B.
Astiella is an herbaceous genus endemic to Madagascar, originally described with a single species A. delicatula Jovet. Molecular and morphological evidence place it in the tribe Spermacoceae s. lat. of Rubiaceae. During herbarium studies and fieldwork in Madagascar, 11 new Astiella species were identified and these are described here: A. antongilensis Groeninckx sp. nov., A. antsalovansis Groeninckx sp. nov., A. confusa Groeninckx sp. nov., A. deblockiae Groeninckx sp. nov., A. desseinii Groeninckx sp. nov., A. homolleae Groeninckx sp. nov., A. latifolia Groeninckx sp. nov., A. longifimbria Groeninckx sp. nov., A. perrieri Groeninckx sp. nov., A. pulla Groeninckx sp. nov., and A. tsaratanensis Groeninckx sp. nov. The genus Astiella now holds 12 species in...
Tipo: Article / Letter to the editor
Palavras-chave: Astiella; Endemism; Madagascar; Rubiaceae; Spermacoceae s. lat.
Ano: 2017
URL: http://www.repository.naturalis.nl/record/629097

Floral Ontogeny in Scirpus, Eriophorum and Dulichium (Cyperaceae), with Special Reference to the Perianth
Provedor de dados: 16
Autores: Vrijdaghs, A.; Caris, P.; Goetghebeur, P.; Smets, E.
Background and Aims Based on molecular phylogenetic analysis, it has been suggested recently that the Cyperaceae comprises only two subfamilies: the Mapanioideae and the Cyperoideae. In most flowers of the Cyperoideae, the whorl of inner stamens is reduced, resulting in tetracyclic flowers. In the more primitive (scirpoid) genera within the Cyperoideae, the perianth consists of two polysymmetric whorls, whereas the perianth parts in the more derived genera have been subject to modifications and/or reduction. Comparative studies of the many silky hairs of Eriophorum and of the eight bristles of Dulichium have given rise to much discussion about their homology.  Methods The spikelet and floral ontogeny in freshly collected inflorescences was investigated...
Tipo: Article / Letter to the editor
Palavras-chave: Dulichium arundinaceum (L.) Britton; Eriophorum latifolium Hoppe; Floral ontogeny; Perianth; Scirpoid flower; Scirpus sylvaticus L; Scanning electron microscopy.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407290

Palynological Variation in Balsaminoid Ericales. II. Balsaminaceae, Tetrameristaceae, Pellicieraceae and General Conclusions
Provedor de dados: 16
Autores: Janssens, S.; Lens, F.; Dressler, S.; Geuten, K.; Smets, E.; Vinckier, S.
Background and Aims The objective of this study is to examine the palynological diversity of Balsaminaceae (two genera/61000 species), Tetrameristaceae (two genera/two species) and Pellicieraceae (one genus/one species). The diversity found will be used to infer the systematic value of pollen features within the balsaminoid clade.  Methods Pollen morphology and ultrastructure of 29 species, representing all families of the balsaminoid clade except Marcgraviaceae, are investigated by means of light microscopy, scanning electron microscopy and transmission electron microscopy.  Key Results Balsaminaceae pollen is small to medium sized with three to four apertures, which can be either colpate or porate, and a sexine sculpturing varying from coarsely...
Tipo: Article / Letter to the editor
Palavras-chave: Balsaminaceae; Ericales; Orbicules; Pellicieraceae; Pollen; SEM; TEM; Tetrameristaceae.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407278

Comparative Wood Anatomy of the Primuloid Clade (Ericales s.l.)
Provedor de dados: 16
Autores: Lens, F.; Jansen, S.; Caris, P.; Serlet, L.; Smets, E.
The wood structure of 78 species from 27 genera representing the woody primuloids (Maesaceae, Myrsinaceae, and Theophrastaceae) was investigated using light microscopy (LM) and scanning electron microscopy (SEM). Results indicated that the ray structure, the nature of mineral inclusions, and the occurrence of breakdown areas in rays can be used to separate the three primuloid families from each other. Within Ericales, the presence of exclusively multiseriate rays is synapomorphic for Myrsinaceae and Theophrastaceae, and the occurrence of breakdown areas in rays is synapomorphic for Myrsinaceae. Within Myrsinaceae, the wood structure of the mangrove genus Aegiceras differs because it has short vessel elements that are storied, non-septate fibers, a...
Tipo: Article / Letter to the editor
Palavras-chave: Primuloids; Ericales s.l.; Maesaceae; Myrsinaceae; Theophrastaceae; Wood anatomy; Comparison; Light microscopy; Scanning electron microscopy.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407307

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

A comparison of paraffin and resin-based techniques used in bark anatomy
Provedor de dados: 16
Autores: Hamann, T.; Smets, E.; Lens, F.
Bark anatomy is an unappreciated discipline in plant systematics, despite its great potential to reveal systematically informative features. In this paper, main reasons for the lack of detailed bark anatomical data in many plant families are identified, including problems with sectioning, terminological issues, and difficulties in observation of dilated stems. We deal with these problems by focusing on two aspects: (1) compare, discuss and improve existing sectioning and maceration techniques using two species with soft and hard bark tissues; and (2) discuss the best way to collect stem bark samples. We hope that this paper will stimulate inclusion of bark anatomical data in future systematic studies.
Tipo: Article / Letter to the editor
Palavras-chave: Bark anatomy; Light microscopy; Macerations; Plant systematics; Phloem; Sectioning; 42.54.
Ano: 2011
URL: http://www.repository.naturalis.nl/record/421834

The multiple fuzzy origins of woodiness within Balsaminaceae using an integrated approach. Where do we draw the line?
Provedor de dados: 16
Autores: Lens, F.; Eeckhout, S.; Zwartjes, R.; Smets, E.; Janssens, S.B.
• Background and Aims: The family Balsaminaceae is essentially herbaceous, except for some woodier species that can be described as ‘woody’ herbs or small shrubs. The family is nested within the so-called balsaminoid clade of Ericales, including the exclusively woody families Tetrameristaceae and Marcgraviaceae, which is sister to the remaining families of the predominantly woody order. A molecular phylogeny of Balsaminaceaeis compared with wood anatomical observations to find out whether the woodier species are derived from herbaceous taxa (i.e. secondary woodiness), or whether woodiness in the family represents the ancestral state for the order (i.e. primary woodiness).  • Methods: Wood anatomical observations of 68 Impatiens species and Hydrocera...
Tipo: Article / Letter to the editor
Palavras-chave: Balsaminaceae; Herbaceousness; Hydrocera; Impatiens; Insular woodiness; Light microscopy; Secondary woodiness; Wood anatomy; 42.56.
Ano: 2012
URL: http://www.repository.naturalis.nl/record/429514

Floral Ontogeny in Ficinia and Isolepis (Cyperaceae), with Focus on the Nature and Origin of the Gynophore
Provedor de dados: 16
Autores: Vrijdaghs, H.; Goetghebeur, P.; Muasya, A.M.; Caris, P.; Smets, E.
! Background and Aims The generic delimitations of Ficinia and Isolepis, sister genera in the Cypereae, are blurred. Typical Ficinia flowers have a lobed gynophore, which envelops the base of the nutlet, whereas in Isolepis the character is considered to be absent. Some former species of Isolepis, lacking the gynophore, were recently included in Ficinia. The floral ontogeny of representative taxa in Ficinia and Isolepis were investigated with the aim of evaluating the origin and nature of the gynophore in the Cypereae. ! Methods The spikelet and floral ontogeny in inflorescences collected in the field was investigated using scanning electron microscopy (SEM) and light microscopy (LM). ! Key Results SEM images of Isolepis setacea and I. antarctica, Ficinia...
Tipo: Article / Letter to the editor
Palavras-chave: Ficinia; Floral ontogeny; Gynophore; Isolepis; Scanning electron microscopy.
Ano: 2005
URL: http://www.repository.naturalis.nl/record/407286

The distribution and phylogeny of aluminium accumulating plants in the Ericales
Provedor de dados: 16
Autores: Jansen, S.; Watanabe, T.; Caris, P.; Geuten, K.; Lens, F.; Pyck, N.; Smets, E.
The distribution of aluminium (Al) accumulation in the Ericales is surveyed, based on semi-quantitative tests of 114 species and literature data. Al accumulation mainly characterises the families Diapensiaceae, Pentaphylacaceae, Symplocaceae, Ternstroemiaceae, and Theaceae. Al accumulation is consistently present or absent in most families examined, but the character appears to be more variable in a few taxa (e.g., Lecythidaceae, Myrsinaceae). Although the interfamilial relationships within the Ericales require further research, the ability to accumulate high levels of Al appears to show considerable taxonomic significance. While the majority of Al accumulating Ericales includes woody, tropical plants, the feature is remarkably present in several...
Tipo: Article / Letter to the editor
Palavras-chave: Aluminium accumulation; Ericales; Phyogeny; Diapensiaceae; Pentaphylacaceae; Symplocaceae; Ternstroemiaceae; Theaceae; 42.56.
Ano: 2004
URL: http://www.repository.naturalis.nl/record/431739

Comparative wood anatomy of epacrids (Styphelioideae, Ericaceae s.l.)
Provedor de dados: 16
Autores: Lens, F.; Gasson, P.; Smets, E.; Jansen, S.
The wood anatomy of 16 of the 37 genera within the epacrids (Styphelioideae, Ericaceae s.l.) is investigated by light and scanning electron microscopy. Several features in the secondary xylem occur consistently at the tribal level: arrangement of vessel‐ray pits, distribution of axial parenchyma, ray width, and the presence and location of crystals. The primitive nature of Prionoteae and Archerieae is supported by the presence of scalariform perforation plates with many bars and scalariform to opposite vessel pitting. The wood structure of Oligarrheneae is similar to that of Styphelieae, but the very narrow vessel elements, exclusively uniseriate rays and the lack of prismatic crystals in Oligarrheneae distinguish these two tribes. The secondary xylem of...
Tipo: Article / Letter to the editor
Palavras-chave: Ecological wood anatomy; Epacrids; Ericaceae s.l.; Styphelioideae; Systematic wood anatomy; 42.56.
Ano: 2003
URL: http://www.repository.naturalis.nl/record/431740