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| Registros recuperados: 13 | |
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| 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 |
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| 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 |
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| 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 |
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| Ano: 1994 |
URL: http://www.repository.naturalis.nl/record/524503 |
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| Weeda, E.J.; Roos, G.Th. de; Robbrecht, E.; Adema, F.; Heukels, P.; Holverda, W.. |
| Over het vroegere voorkomen van Chenopodium vulvaria L. in Nederland. Naar aanleiding van een recente vondst van Chenopodium vulvaria bij Assendelft schrijft MENNEMA (1977): „Met P. Heukels, die het verspreidingskaartje gereed maakte voor de Atlas van de Nederlandse Flora, ben ik van mening, dat in Nederland alleen Z.-Limburg tot het areaal van C. vulvaria mag worden gerekend”. Hierbij zou ik de volgende kanttekeningen willen maken: C. vulvaria wordt onder de naam Atriplex olida door VORSTIUS (1633) voor de omgeving van Leiden en door BRUMAN (1662) voor die van Zwolle opgegeven. MEESE (1760, p. 15, nr. 113) geeft op: „Overal in Moes-hoven, en aan de weegen”, BRUINSMA (1840, p. 57, als C. foetidum): „bij Harlingen en Leeuward.” Dat deze soort, hoewel... |
| Tipo: Article / Letter to the editor |
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| Ano: 1979 |
URL: http://www.repository.naturalis.nl/record/526798 |
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| 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 |
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| 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 |
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| 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 μm. 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 |
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| Ali, S.J.; Robbrecht, E.. |
| The Asian and Australian species generally included in Diplospora or Tricalysia are shown to form an artificial assemblage. A few species even do not belong to the Gardenieae-Diplosporinae and need to be transferred to other tribes of the Ixoroideae. So Diplospora malaccensis, Diplospora minahassae, Tricalysia purpurea, and Tricalysia sorsogonensis belong to the Hypobathreae. The three Australian Diplosporas are members of the Pavetteae and are transferred to Tarenna. A survey is given of the characters of the remaining Asian species of Diplospora/Tricalysia, demonstrating that 1) these species cannot be accommodated under the African genus Tricalysia, and 2) Discospermum, since a century included in the synonymy of Diplospora, merits to be revived at... |
| Tipo: Article / Letter to the editor |
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| Ano: 1991 |
URL: http://www.repository.naturalis.nl/record/524464 |
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| Robbrecht, E.; Puff, C.; Igersheim, A.. |
| The two species of Mitchella (Southeast Asian and North American) and several species of the Southeast Asian genus Damnacanthus are investigated. Vegetative character states (growth form, branching pattern, leaves) of the two genera are described and compared. Damnacanthus always exhibits heterophylly and some species have paired thorns. The latter are interpreted as paired lateral shoots in the proximal part of a sympodial branch unit, and it is speculated that the paired thorns may be modified inflorescence shoots. Detailed information is also given on inflorescence structure and floral morphological and anatomical details of Damnacanthus and Mitchella. Particular emphasis is placed on the ovaries, the structure of which is remarkably similar in the two... |
| Tipo: Article / Letter to the editor |
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| Ano: 1991 |
URL: http://www.repository.naturalis.nl/record/525774 |
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| 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 |
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| Registros recuperados: 13 | |
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