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| Registros recuperados: 31 | |
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| Ham, R.W.J.M. van der. |
| Mischocarpus Blume, Bijdr. (1825) 238, nom. cons.; Rumphia 3 (1849) 166; Radlk., Pfl. R. Heft 98 (1933) 1288—1310. — Cupania § Mischocarpus Miq., Fl. Ind. Bat. I, 2 (1859) 566. — Type: M. sundaicus Bl. Pedicellia Lour., Fl. Coch. (1790) 655, nom. rejic. (see under dubious names). — Type: P. oppositifolia Lour. Mischocodon Radlk., Bot. jahrb. 50 (1913) 79; Pfl. R. Heft 98 (1933) 1327—1328. — Type: M. reticulatus Radlk. Shrubs or, sometimes large, trees, sometimes with a slender unbranched stem. Buttresses sometimes present (M. largifolius). Indumentum rather dense to sometimes very sparse, consisting of mostly appressed, short to long, brownish to ferruginous hairs; no glandular scales. Twigs brownish to reddish-brown to greyish. Axillary buds just above... |
| Tipo: Article / Letter to the editor |
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| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/524863 |
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| Ham, R.W.J.M. van der. |
| During a revision of herbarium material of the genus Barbarea, it became apparent that Barbarea intermedia Bor. is much more common in the Netherlands than was supposed. It is probably a native rather than a casual species although it may have been introduced long ago. Barbarea verna (Mill.) Aschrs., usually thought of as a rare native species, appears to be merely a casual in the Netherlands. |
| Tipo: Article / Letter to the editor |
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| Ano: 1982 |
URL: http://www.repository.naturalis.nl/record/526952 |
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| Adema, F.; Ham, R.W.J.M. van der. |
| Cladistic analyses of pollen-morphological, leaf-anatomical and macromorphological data of Jagera, Trigonachras, and several new species lead to the conclusion that a new genus, Cnesmocarpon, has to be described (see the Taxonomic Part on p. 195). Two pollen types are described, one including Cnesmocarpon, the other including Jagera and Trigonachras. The morphologies of these pollen types suggest different harmomegathic systems: nonapertural and apertural folding respectively. The ornamentation of Cnesmocarpon pollen resembles that of several other Cupanieae genera. The scabrate ornamentation of Jagera and Trigonachras pollen, often provided with hair-like appendages, is unique in that tribe. Leaf-anatomically Jagera is characterised by the presence of... |
| Tipo: Article / Letter to the editor |
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| Ano: 1993 |
URL: http://www.repository.naturalis.nl/record/526125 |
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| Ham, R.W.J.M. van der; Meijden, Ruud van der. |
| In the last years isolated specimens of Daphne laureola have been found in three localities in the Netherlands: one in the dunes of Voorne, and two in public gardens in Delft. Daphne laureola is only rarely cultivated in the Netherlands. It is argued that the Dutch localities might belong to a more or less natural extension of the distribution area of this species, which might be associated with the still ameliorating climatic conditions for atlantic-mediterranean species in the Netherlands. |
| Tipo: Article / Letter to the editor |
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| Ano: 2001 |
URL: http://www.repository.naturalis.nl/record/526810 |
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| Ham, R.W.J.M. van der; Heuven, B.J. van. |
| A pollen morphological survey of the genus Guioa is presented. Based on a study of the harmomegathy in relation to morphological series, evolutionary trends are postulated: 1. wide ectoapertures → narrow ectoapertures 2. grain parasyncolporate → grain colporate 3. grain parasyncolporate → grain syncolporate 4. ornamentation rugulate → ornamentation psilate-imperforate. It is suggested that the most ‘primitive’ species of Guioa occur in the southeastern part of the distribution area of the genus. Guioa can be subdivided into four poorly delimited pollen morphological groups. Its affinities to other genera in the Cupanieae are briefly discussed. Pollen of the most ‘primitive’ group is similar to that of several ‘primitive’ genera (e.g. Arytera, Matayba,... |
| Tipo: Article / Letter to the editor |
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| Ano: 1989 |
URL: http://www.repository.naturalis.nl/record/525415 |
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| Ham, R.W.J.M. van der. |
| Induced by too many wrongly determined specimens of Lactuca virosa L. the author discusses a number of differences with Lactuca serriola L. The fruit especially offers reliable characters (fig. 3). L. virosa probably occurs only as an alien in the Netherlands. In recent years L. serriola had a considerable expansion, particularly in the urbanized west of the country. Very often it concerns f. integrifolia Bogenhard. Nowadays, this forma seems to be more common than in former years. |
| Tipo: Article / Letter to the editor |
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| Ano: 1981 |
URL: http://www.repository.naturalis.nl/record/527578 |
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| Ham, R.W.J.M. van der. |
| The occurrence of Viburnum lantana in the Netherlands is discussed, with reference to the identification of a shrub belonging to this species in the painting 'Dunes by the Sea' (1648) by Jacob van Ruisdael and its naturalness in the dunes near Haarlem (Ashton c.s., 1982). Although Van Ruisdael worked most accurately in depicting trees and shrubs, he took many liberties in the composition of a painting. As V. lantana was already cultivated in his century, it is possible that he saw the species in cultivation and then 'introduced' it in 'Dunes by the Sea'. All other records of the species in the vicinity of Haarlem point to an origin as garden escape. |
| Tipo: Article / Letter to the editor |
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| Ano: 1983 |
URL: http://www.repository.naturalis.nl/record/526898 |
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| Ham, R.W.J.M. van der; Meijden, R. van der. |
| Afwijkingen bij Setaria viridis (L.) Beauv. en Setaria verticillata (L.) Beauv. Onder het in 1982 verzamelde herbariummateriaal troffen wij een exemplaar van Setaria viridis aan, afkomstig van Steenwijk (kilometerhok 16.45.24), waarbij de borstels onder de aartjes met naar achter gerichte haakjes waren bezet (van onder naar boven gaande voelt de bloeiwijze dan ruw aan). Dit kenmerk wordt als exclusief voor Setaria verticillata beschouwd en het materiaal was dan ook als zodanig gedetermineerd. Bij S. viridis was een dergelijke afwijking ons niet bekend. Bij S. verticillata komen afwijkende exemplaren, met naar voren gerichte haakjes op de borstels (van onder naar boven gaande voelt de bloeiwijze dan glad aan), vrii regelmatig voor. Bij het determineren van... |
| Tipo: Article / Letter to the editor |
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| Ano: 1984 |
URL: http://www.repository.naturalis.nl/record/526567 |
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| Adema, F.; Ham, R.W.J.M. van der; Hartog, C. den; Ploeg, D.T.E. van der; Weeda, E.J.. |
| Een nieuwe desinfectiemethode voor herbaria. Droog organisch materiaal oefent een grote aantrekkingskracht uit op allerlei dierlijke organismen. Gedroogde planten, het herbarium, maken daarop geen uitzondering en worden met graagte door verschillende insektesoorten gegeten. Vooral de z.g. museumkevers worden nogal eens in collecties aangetroffen. Iedereen, die er een herbarium op na houdt, weet, dat regelmatige controle en desinfectie van zijn collectie noodzakelijk zijn. Het controleren van vele, soms duizenden of tienduizenden, exemplaren is een tijdrovend, zij het niet altijd onplezierig karweitje. Het desinfecteren van een collectie kan echter wel onplezierig zijn. Om een herbarium insektenvrij te houden, wordt tot nu toe gewerkt met bepaalde... |
| Tipo: Article / Letter to the editor |
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| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/528088 |
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| Bergen, M.A. van; Ham, R.W.J.M. van der; Turner, H.. |
| A description of Arytera pollen based on light and scanning electron microscopic observations is presented. Four aperture types and two ornamentation types (one divided into two subtypes) can be distinguished. The commonest aperture types are colporate and parasyncolporate; each of the other two types occurs in a single species. The main ornamentation types are rugulate and striate-rugulate; the latter has small or large lumina. Polymorphism occurs in both characters in several species. A cladistic analysis of Arytera shows two distinct evolutionary trends in the pollen: 1) aperture system from parasyncolporate to colporate, and 2) ornamentation from striate-rugulate with small lumina to striate-rugulate with large lumina. The plesiomorphic state of the... |
| Tipo: Article / Letter to the editor |
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| Ano: 1995 |
URL: http://www.repository.naturalis.nl/record/526177 |
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| Ham, R.W.J.M. van der. |
| Two main types may be distinguished within Alectryon pollen: the colporate type and the parasyncolporate type. These types are not clear-cut, but merge into each other through a complete series of intermediate forms. The colporate type has usually a colporate apertural system, a high P/E value (av. 0.97), a low A/E value (0.32), and striate to striate-rugulate ornamentation. The parasyncolporate type shows usually a parasyncolporate apertural system, a low P/E value (av. 0.76), a high A/E value (av. 0.46), and striate-rugulate to rugulate ornamentation. In addition, there is some difference in endoaperture and nexine morphology, and the relative length of the peripheral columellae of a mesocolpium. An endoaperture in a colporate grain often shows acute or... |
| Tipo: Article / Letter to the editor |
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| Ano: 1990 |
URL: http://www.repository.naturalis.nl/record/508210 |
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| Ham, R.W.J.M. van der. |
| Consequently upon a revision of Mischocarpus (Van der Ham, 1977a), a detailed study has been made of several characters in Arytera in order to get a better understanding of the delimitation of the two genera mutually. The differences between Mischocarpus and Arytera given by Radlkofer (1931) in his key are vague and can only be used when fruiting material is available. However, several species in Arytera were described by him and others on flowering material only. Two species of Mischocarpus could be connected with species of Arytera. One species of Arytera appeared to be the same as Mischocarpus exangulatus. M. exangulatus has, besides typical Mischocarpus characters, several features unique in Mischocarpus but more regularly occurring in Arytera.... |
| Tipo: Article / Letter to the editor |
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| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/525431 |
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| Registros recuperados: 31 | |
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