SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

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...

Khmeriosicyos, a new monotypic genus of Cucurbitaceae from Cambodia

Ano: 1995

URL: http://www.repository.naturalis.nl/record/526177

Wilde, W.J.J.O. de; Duyfjes, B.E.E.; Ham, R.W.J.M. van der.

A new monotypic genus from Cambodia is described. The genus is defined by a unique combination of characters and has distinct pollen features. The only species is Khmeriosicyos harmandii W.J. de Wilde & Duyfjes.

Rare conifers from the type area of the Maastrichtian (Upper Cretaceous, southeast Netherlands)

Palavras-chave: Cucurbitaceae; Khmeriosicyos; New genus; Pollen; SE Asia.

Ano: 2004

URL: http://www.repository.naturalis.nl/record/525002

Ham, R.W.J.M. van der; Konijnenburg-van Cittert, J.H.A. van.

Two conifer twigs from the type area of the Maastrichtian are described as Brachyphyllum sp. 1 and Brachyphyllum sp. 2. They might belong to the Cheirolepidiaceae, Podocarpaceae or Taxodiaceae. Brachyphyllum sp. 1 occurs with the conifers Brachyphyllum patens (?Cheirolepidiaceae) and Elatidopsis cryptomerioides (Taxodiaceae), the seagrass Thalassocharis bosqueti and the ammonite Baculites vertebralis in the upper part of the Kunrade Chalk in the Kunrade area, while Brachyphyllum sp. 2 probably originates from the lower part of this deposit.

Nephelieae pollen (Sapindaceae): Form, function, and evolution

Palavras-chave: Brachyphyllum; Conifer; Maastrichtian; Kunrade Chalk; 38.21.

Ano: 2003

URL: http://www.repository.naturalis.nl/record/219297

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...

Curtia ayangannae, a new species of Gentianaceae from the Pakaraima Mountains, Guyana

Ano: 1990

URL: http://www.repository.naturalis.nl/record/508210

Cobb, L.; Jansen-Jacobs, M.J.; Ham, R.W.J.M. van der.

A new species of Curtia (Gentianaceae: Saccifolieae), C. ayangannae L. Cobb & Jans.-Jac., from Mt Ayanganna, Guyana, is described and illustrated. The relationship between the genera Curtia, Tapeinostemon, and Saccifolium is discussed.

Papuasicyos, a new genus of Cucurbitaceae

Palavras-chave: Gentianaceae; Curtia; Pakaraima Mountains; Guyana; South America; Taxonomy.

Ano: 2007

URL: http://www.repository.naturalis.nl/record/525398

Duyfjes, B.E.E.; Ham, R.W.J.M. van der; Wilde, W.J.J.O. de.

A new monotypic genus from New Guinea is described. Its pollen matches that of the Cucurbitoieae–Melothrieae, except for its small size.

De nerfamarant (Amaranthus blitoides S. Wats.) in Nederland

Ano: 2003

URL: http://www.repository.naturalis.nl/record/525044

New data are given to amplify the tentative remarks on naturalization of Amaranthus blitoides S. Wats, in the Atlas of the Netherlands Flora (Van der Ham, 1980). Although merely of casual occurrence in some localities, the species is thought to be naturalized in the dunes, along the river Waal and in urban areas. It was first found in 1900.

Ano: 1982

URL: http://www.repository.naturalis.nl/record/526428

Korte mededeling

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...

Myriophyllum aquaticum (Veil.) Verdc. verwilderd gevonden bij Moordrecht

Ano: 1984

URL: http://www.repository.naturalis.nl/record/526567

Myriophyllum aquaticum, an aquatic plant from tropical and subtropical South America, has been found abundantly in a small ditch near Moordrecht (prov. Zuid-Holland). Plants escaped from a nursery in 1982 and survived the mild winter 1982-’83, grew luxuriously during the hot summer of 1983.

Pollen of Southeast Asian Alchornea (Euphorbiaceae), with an overview of the pollen fossil record

Ano: 1984

URL: http://www.repository.naturalis.nl/record/527933

Bulalacao, L.J.; Ham, R.W.J.M. van der.

In order to evaluate pollen morphological descriptions of Alchornea in the literature, which are almost completely based on African and American species, the pollen of eight Southeast Asian species of Alchornea was investigated, using light and scanning electron microscopy. Very little variation appeared to be present in the Asian material. Slightly deviating from the scabrate ornamentation type are A. kelungensis (psilate) and A. rugosa (striate-rugulate). The scabrate type is also found in A. castaneaefolia (Brazil), A. hirtella (Liberia) and A. obovata (Colombia). The operculate Alchornea pollen type, which can be easily recognised using light microscopy, seems to represent a diagnostic character for the tribe Alchornieae (pollen of Bossera unknown)....

Is Viburnum lantana L. indigeen in de duinen bij Haarlem?

Palavras-chave: Alchornea; Euphorbiaceae; Fossil record; Pollen; SE Asia.

Ano: 2003

URL: http://www.repository.naturalis.nl/record/525434

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.