Peter van Welzen
Hoogleraar Biologie
- Naam
- Prof.dr. P.C. van Welzen
- Telefoon
- +31 71 527 2727
- peter.vanwelzen@naturalis.nl
Meer informatie is beschikbaar op de Engelse profielpagina.
Promovendi
Nieuws
Hoogleraar Biologie
- Wiskunde en Natuurwetenschappen
- Instituut Biologie Leiden
- IBL Algemeen
- Welzen P.C. van, Hilgen S.J., Klink J.M.A, Yu R.Y. & Zelfde M. van 't (2024), Botanical dispersal pathways into Malesia: the Philippines – Southeast Asian connection, Blumea 69(2): 171-195.
- Welzen P.C. van, Winkel E.L.C. & Bouman R.W. (2023), Parallel developments in floral adaptations to obligate moth pollination mutualism in tribe Phyllantheae (Phyllanthaceae), PhytoKeys 225: 165-198.
- Bouman R.W., Kessler P.J.A., Telford I.R.H., Bruhl J.J., Strijk J.S., Saunders R.M.K., Esser H.-J., Falcón-Hidalgo B. & Welzen P.C. van (2023), Erratum: Bouman, R.W., Keβler, P.J.A., Telford, I.R.H., Bruhl, J.J., Strijk, J.S., Saunders, R.M.K., Esser, H.-J., Falcón-Hidalgo, B. & van Welzen, P.C. (2022) A revised phylogenetic classification of tribe Phyllantheae (Phyllanthaceae). Phytotaxa 540: 1–100, Phytotaxa 597(3): 237-241.
- Kartonegoro A., Mota de Oliveira S. & Welzen P.C. van (2022), Historical biogeography of the Southeast Asian and Malesian tribe Dissochaeteae (Melastomataceae), Journal of Systematics and Evolution 60(2): 237-252.
- Bouman R.W., Kessler P.J.A., Telford I.R.H., Bruhl J.J., Strijk J.S., Saunders R.M.K., Esser H.J., Falcón-Hidalgo B. & Welzen P.C. van (2022), A revised phylogenetic classification of tribe Phyllantheae (Phyllanthaceae), Phytotaxa 540(1): 1-100.
- Welzen P.C. van, Arias Guerrero S., Arifiani D., Bangun T.J.F., Bouman R.W., Furlings M.C.M., Gushilman I., Phillipson P.B., Tabak I., Winkel E. & Wurdack K.J. (2021), Weda, a new genus with two new species of Euphorbiaceae‐Crotonoideae from Halmahera (North Maluku, Indonesia) and phylogenetic relationships of the Australasian tribe Ricinocarpeae, Journal of Systematics and Evolution 59(5): 1000-1017.
- Bouman R.W., Kessler P.J.A., Telford I.R.H., Bruhl J.J., Strijk J.S., Saunders R.M.K. & Welzen P.C. van (2020), Molecular phylogenetics of Phyllanthus sensu lato (Phyllanthaceae): Towards coherent monophyletic taxa, Taxon 70(1): 72-98.
- Verwijs J.I.M. Bouman R.W. Welzen P.C. van (2019), A taxonomic revision of Phyllanthus subgenus Macraea (Phyllanthaceae), Blumea 64: 231-252.
- Bouman R.W., Kessler P.J.A. & Welzen P.C. van (2019), Lectotypification and amended description of Phyllanthus (phyllanhaceae) species described by Koorders from Sulawesi, Indonesia, Reinwardtia 18(2): 97-103.
- Sirichamorn Y., Adema F.A.C.B. & Welzen P.C. van (2013), Proposal to conserve the name Brachypterum against Solori (Fabaceae), Taxon 62: 179-180.
- Welzen P.C. van, Gadella T.W.J., Maas P.J.M., Daly D.C., Mori S.A., Jørgensen P.M., Obermüller F.A., Kjellberg F., Rønsted N., Chantarasuwan B. & Lut C.W.J. (2013), In memoriam Cees Berg (2 July 1934 -- 31 August 2012), Blumea: Biodiversity, Evolution and Biogeography of Plants 57: 199-206.
- Stoops E. & Welzen P.C. van (2013), A revision of Ptychopyxis (Euphorbiaceae) in Southeast Asia, Nordic Journal of Botany 31: 94-112.
- Sirichamorn Y., Adema F.A.C.B., Gravendeel B. & Welzen P.C. van (2012), Phylogeny of Palaeotropic Derris-like Taxa (Fabaceae) based on chloroplast and nuclear DNA sequences shows reorganization of (infra)generic classifications is needed, American Journal of Botany 99(11): 1793-1808.
- Nucete M., Konijnenburg-Van Cittert J.H.A. van & Welzen P.C. van (2012), Fossils and palaeontological distributions of Macaranga and Mallotus (Euphorbiaceae). Palaeogeography, Palaeoclimatology, Palaeoecology. 104-115.
- Wilkin P., Suksathan P., Keeratikiat K., Welzen P.C. van & Wiland-Szymańska J. (2012), A new threatened endemic species from central and northeastern Thailand, Dracaena jayniana (Asparagaceae: tribe Nolinoideae), Kew Bull. 67: 1-9.
- Pruesapan K., Telford I.R.H., Bruhl J.J. & Welzen P.C. van (2012), Phylogeny and proposed circumscription of Breynia, Sauropus and Synostemon (Phyllanthaceae), based on chloroplast and nuclear DNA sequences, Australian Systematic Botany 25: 313-330.
- Baas P., Roos M.C. & Welzen P.C. van (2012), On Max van Balgooy's 80th birthday, Blumea: Biodiversity, Evolution and Biogeography of Plants 57: 103-104.
- Fišer Pečnikar Ž., Kulju K.K.M., Sierra S.E.C., Baas P. & Welzen P.C. van (2012), Leaf anatomy of Mallotus and the related genera Blumeodendron and Hancea (Euphorbaceae sensu stricto), Botanical Journal of the Linnean Society 169: 645-676.
- Sirichamorn Y., Adema F.A.C.B. & Welzen P.C. van (2012), The Genera Aganope, Derris, and Paraderris (Fabaceae, Millettieae) in Thailand, Systematic Botany 37(2): 404-436.
- Welzen P.C. van, Madern A., Raes N., Parnell J.A.N., Simpson D.A., Byrne C., Curtis T., Mackling J., Trias-Blasi A., Prajaksood A., Bygrave P., Larsen K., Larsen S.S., Nielsen I., Meade C., Middleton D.J., Pendry A.C., Muasya A.M., Dransfield S., Kirkup D.W., Moat J., Wilkin P., Couch C., Boyce P.C., Chayamarit K., Chantarnothai P., Esser H-J., Jebb M.H.P., Phattharahirantricin N., Pooma R., Suddee S., Staples G.W., Sungkaew S. & Teerawatananon A. (2011), The Current and Future Status of Floristic Provinces in Thailand. In: Trisurat Yongyut, Shrestha Rajendra P. & Alkemade Rob (red.), Land Use, Climate Change and Biodiversity Modeling: Perspectives and Applications. U.S.A.: Information Science Reference. 219-247.
- Welzen P.C. van & Forster P.I. (2011), Picrodendraceae. In: Nooteboom H.P. (red.), Flora Malesiana. Leiden: Foundation Flora Malesiana.
- Acevedo-Rodriguez P., Welzen P.C. van, Adema F.A.C.B. & Ham R.W.J.M. van der (2011), Sapindaceae. In: Kubitzki K. (red.), The families and genera of vascular plants 10, Flowering plants, Eudicots, Sapindales, Cucurbitales, Myrtales 357-407, figs 76-86.
- Welzen P.C. van (2011), Pandaceae. In: Nooteboom H.P. (red.), Flora Malesiana. Leiden: Foundation Flora Malesiana.
- Welzen P.C. van (2011), Floristic regions in Thailand, now and in the future, 15th Flora of Thailand Meeting (7-11 Nov. Chiang Mai): 20.. .
- Wilkin P., Suksathan K., Keeratikiat K., Welzen P.C. van & Wiland-Szymanska J. (2011), The diversity of Dracaena L. in Thailand, 15th Flora of Thailand Meeting : .
- Welzen P.C. van, Nucete M. & Konijnenburg-Van Cittert J.H.A. van (2011), Fossil Macaranga and Mallotus (Euphorbiaceae): What to believe?, 15th Flora of Thailand Meeting : .
- Telford I.R.H., Pruesapan K., Welzen P.C. van & Bruhl J.J. (2011), When in doubt, put it in Phyllanthus (Phyllanthaceae): towards dismembering a giant genus. [overig].
- Sirichamorn Y., Adema F.A.C.B. & Welzen P.C. van (2011), Systematics of the genus Derris Lour. (Fabaceae) and its closely related genera in Thailand, 15th Flora of Thailand Meeting : .
- Raes N., Kessler P.J.A., Roos M.C., Saw L.G., Slik J.W.F. & Welzen P.C. van (2011), Glacial refugia of the Sunda Shelf and their impact on current species' distributions. [overig].
- Chantarasuwan B., Berg C.C. & Welzen P.C. van (2011), A revision of Ficus subsection Urostigma (Moraceae), 15th Flora of Thailand Meeting : .
- Welzen P.C. van, Hovenkamp P.H. & Turner H. (2011), Pathways through Malesia. [overig].
- Arias Guerrero S. & Welzen P.C. van (2011), Revision of Malesiana Endospermum (Euphorbiaceae) with notes on phylogeny and historical biogeography. Edinburgh J. Bot, Flora Malesiana Bulletin 68: 443-482.
- Welzen P.C. van (2011), Revision of Dicolia (Phyllanthaceae; Euphorbiaceae s.l.), Blumea: Biodiversity, Evolution and Biogeography of Plants 56: 209-213.
- Welzen P.C. van & Raes N. (2011), The floristic position of Java, Gard. Bull. Singapore 63(1 & 2): 329-339.
- Welzen P.C. van, Parnell J.A.N. & Slik J.W.F. (2011), Wallace's Line and plant distributions: two or three phytogeographical areas and where to group Java?, Biological Journal of the Linnean Society 103: 531-545.
- Roos M.C., Berendsohn W.G., Dessein S., Hamann T., Kirkup D.W., Kok R.P.J. de, Sierra Daza S.E.C., Smets E., Webb C.O. & Welzen P.C. van (2011), e-Flora Malesiana: state of the art and perspectives, Gard. Bull. Singapore 63(1 & 2): 189-195.
- Welzen P.C. van & Forster P.I. (2010), A revision of Malesian Austrobuxus (Picrodendraceae/Euphorbiaceae s.l. subfam. Oldfieldioideae), Nordic Journal of Botany 28: 189-195.
- Sierra S.E.C., Kulju K.K.M., Fišer Ž, Aparicio M. & Welzen P.C. van (2010), The phylogeny of Mallotus s.s. (Euphorbiaceae s.s.) inferred from DNA sequence and morphological data, Taxon 59: 101-116.
- Welzen P.C. van, Kulju K.K.M., Sierra S.E.C. & Slik J.W.F. (2010), Key to the Malesian species of Mallotus (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 55: 285-290.
- Chantarasuwan B., Berg C.C. & Welzen P.C. van (2010), Taxonomy and Systematics of Ficus subsection Urostigma (Moraceae). [overig].
- Welzen P.C. van & Raes N. (2010), The floristic position of Java. [overig].
- Sirichamorn Y., Adema F.A.C.B. & Welzen P.C. van (2010), The genera Aganope, Derris and Paraderris (Fabaceae) in Thailand. [overig].
- Pruesapan K., Telford I.R.H., Bruhl J.J., Esser H-J. & Welzen P.C. van (2010), Synostemon reinstated and Sauropus sensu stricto transferred to Breynia (Phyllanthaceae) based on molecular and morphological phylogenetic evidence. [overig].
- Welzen P.C. van (2010), Revision of the Asian genus Koilodepas (Euphorbiaceae), Ann. Missouri Bot. Gard. 97: 218-234.
- Hou D. & Welzen P.C. van (2010), Celastraceae, Flora of Thailand 10(2): 141-198.
- Barker C. & Welzen P.C. van (2010), Flueggia (Euphorbiaceae s.l. or Phyllantyhaceae) in Malesia, Syst. Bot. 35: 541-551.
- Welzen P.C. van & Pruesapan K. (2010), Four new species of Breynia (Phyllanthaceae/Euphorbiaceae sensu lato) and one new combination from Thailand and Malaysia, Thai For. Bull. 38: 111-119.
- Welzen P.C. van (2010), Leeaceae, Flora of Thailand 10(2): 209-230.
- Sagun V.G., Levin G.A. & Welzen P.C. van (2010), Revision and phylogeny of Acalypha (Euphorbiaceae) in Malesia, Blumea: Biodiversity, Evolution and Biogeography of Plants 55: 21-60.
- Welzen P.C. van & Slik J.W.F. (2009), Patterns in species richness and composition of plant families in the Malay Archipelago, Blumea: Biodiversity, Evolution and Biogeography of Plants 54: 166-171.
- Welzen P.C. van, Kulju K.K.M. & Sierra S.E.C. (2009), How to tackle revisions of large genera: lessons from Macaranga and Mallotus (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 54: 25-28.
- Raes N. & Welzen P.C. van (2009), "The demarcation and internal division of Flora Malesiana: 1857 - present.", Blumea: Biodiversity, Evolution and Biogeography of Plants 54: 6-8.
- Kabouw P., Welzen P.C. van, Baas P. & Heuven B.J. van (2008), Styloid crystals in Claoxylon (Euphorbiaceae) and allies (Claoxylinae) with notes on leaf anatomy, Botanical Journal of the Linnean Society 156: 445-457.
- Willemse L.P.M., Welzen P.C. van & Mols J.B. (2008), Point of View. Standardisation in data-entry across databases: avoiding Babylonian confusion, Taxon 57(2): 1-3.
- Willemse L.P.M., Welzen P.C. van & Mols J.B. (2008), Standardisation in data-entry across databases: avoiding Babylonian confusion, Taxon 57: 343-345.
- Pruesapan K., Telford I.R.H., Bruhl J.J., Draisma S.G.A. & Welzen P.C. van (2008), Delimitation of Sauropus (Phyllanthaceae) Based on Plastid matK and Nuclear Ribisomal ITS DNA Sequence Data, Ann. Bot. 102: 1007-1018.
- Welzen P.C. van (2008), Sabiaceae. In: Santisuk T. & Larsen K. (red.), Flora of Thailand. Bangkok: The Forest Herbarium. 91-94.
- Welzen P.C. van & Veldkamp J.F. (2008), Trigoniaceae. In: Santisuk T. & Larsen K. (red.), Flora of Thailand. Bangkok: The Forest Herbarium. 173-175.
- Kulju K.K.M. & Welzen P.C. van (2008), Proposal to conserve the name Mallotus against Trevia (“Trewia”) (Euphorbiaceae s.str.), Taxon 57: 1359-1360.
- Kulju K.K.M., Sierra S.E.C., Draisma S.G.A., Samuel R. & Welzen P.C. van (2007), Molecular phylogeny of Macaranga, Mallotus, and related genera (Euphorbiaceae s.s.): insights from plastid and nuclear DNA sequence data, American Journal of Botany 94: 1726-1743.
- Sierra S.E.C., Aparicio M., Gebraad M.J.H., Kulju K.K.M. & Welzen P.C. van (2007), The morphological range in Mallotus and a taxonomic revision of its section Rottleropsis (including Axenfeldia) in Malesia, Thailand and Africa, Blumea: Biodiversity, Evolution and Biogeography of Plants 52: 21-113.
- Welzen P.C. van (2007), Euphorbiaceae of Papua. In: Marshall A.J. & Beehler B.M. (red.), The ecology of Indonesia Series, Volume VI: The ecology of Papua, pt. 1:. Singapore: Periplus Editions. 394-398.
- Sierra S.E.C., Aparicio M., Kulju K.K.M., Fišer Ž, Welzen P.C. van & Ham R.W.J.M. van der (2007), Re-shaping Mallotus [Part 1]: Expanded circumscription and revision of the genus Cordemoya (Euphorbiaceae). In: Sierra Daza S.E.C. (red.), Re-shaping spurge pioneers. Circumscription, taxonomy and phylogeny of Mallotus (Euphorbiaceae s.s.). Leiden: National Herbarium Nederland. 63-82.
- Welzen P.C. van (2007), Sapindaceae of Papua. In: Marshall A.J. & Beehler B.M. (red.), The ecology of Indonesia Series, Volume VI: The ecology of Papua, pt. 1. Singapore: Periplus Editions. 447-461.
- Welzen P.C. van, Sierra S.E.C. & Silk J.W.F. (2007), Mallotus. In: Welzen P.C. van & Chayamarit K. (red.), Flora of Thailand. Bangkok: The Forest Herbarium 8. 384-437.
- Welzen P.C. van & Bulalacao L.J. (2007), The genus Alchornea (Euphorbiaceae) in the Malay Archipelago and Thailand, Systematic Botany 32: 803-818.
- Kulju K.K.M., Sierra S.E.C. & Welzen P.C. van (2007), Re-shaping Mallotus [Part 2]: Inclusion of Neotrewia, Octospermum and Trewia to Mallotus s.s. (Euhporbiaceae s.s.), Blumea: Biodiversity, Evolution and Biogeography of Plants 52: 115-136.
- Sierra S.E.C., Kulju K.K.M., Veldkamp J.F. & Welzen P.C. van (2007), Resurrection of Hancea and lectotypification of Adisca (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 52: 361-366.
- Sierra S.E.C. & Welzen P.C. van (2006), Mallotus kongkandae (Euphorbiaceae): New record for China, Blumea: Biodiversity, Evolution and Biogeography of Plants 51: 365-366.
- Welzen P.C. van, Sierra S.E.C., Gebraad M.J.H. & Kulju K.K.M. (2006), The distinction of five Mallotus species formerly in section Hancea (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 51: 367-372.
- Sierra S.E.C., Aparicio M., Kulju K.K.M., Fiser Z., Welzen P.C. van & Ham R.W.J.M. van der (2006), Re-shaping Mallotus [Part 1]: Expanded circumscription and revision of the genus Cordemoya (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 51: 519-540.
- Welzen P.C. van & Sierra S.E.C. (2006), The Mallotus wrayi complex (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 51: 373-388.
- Welzen P.C. van & Phonsena P. (2005), Lepisanthes amoena (Hassk.) Leenh. (Sapindaceae), a new record for Thailand, Thai For. Bull. 32: 170-172.
- Sam Hoang. van & Welzen P.C. van (2005), Revision of Annesijoa, Elateriospermum and the introduced species of Hevea in Malesia (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 49: 425-440.
- Sierra S.E.C. & Welzen P.C. van (2005), A taxonomic revision of Mallotus section Mallotus (Euphorbiaceae) in Malesia, Blumea: Biodiversity, Evolution and Biogeography of Plants 50: 249-274.
- Welzen P.C. van & Sierra S.E.C. (2005), Lasiococca brevipes (Euphorbiaceae): a new combination, Blumea: Biodiversity, Evolution and Biogeography of Plants 50: 275-277.
- Kulju K.K.M. & Welzen P.C. van (2005), Revision of the genus Cleidion (Euphorbiaceae) in Malesia, Blumea: Biodiversity, Evolution and Biogeography of Plants 50: 197-219.
- Welzen P.C. van (2005), A new combination in Meliosma (Sabiaceae), Thai For. Bull. 32: 168-169.
- Sierra S.E.C., Welzen P.C. van & Slik J.W.F. (2005), A taxonomic revision of Mallotus section Philippinensis (former section Rottlera Euphorbiaceae) in Malesia and Thailand, Blumea: Biodiversity, Evolution and Biogeography of Plants 50: 221-248.
- Welzen P.C. van, Slik J.W.F. & Alahuhta J. (2005), Plant distribution patterns and plate tectonics in Malesia, Biologiske skrifter 55: 199-217.
- Welzen P.C. van, Ham R.W.J.M. van der & Kulju K.K.M. (2005), Mallotus glomerulatus (Euphorbiaceae), a new species: its description, pollen, and phylogenetic position, Thai For. Bull. 32: 173-178.
- Hoang Sam. van & Welzen P.C. van (2004), Revision of Annesijoa, Elateriospermum and the introduced species of Hevea in Malesia (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 49: 425-440.
- Welzen P.C. van, Ham R.W.J.M. van der & Kulju K.K.M. (2004), Mallotus glomerulatus (Euphorbiaceae), a new species: its description, pollen and phylogenetic position, Thai For. Bull. 32: 173-178.
- Welzen P.C. van & Phonsena P. (2004), Lepisanthes amoena (Hassk.) Leenh. (Sappindaceae), a new record for Thailand, Thai For. Bull. 32: 170-172.
- Welzen P.C. van, Turner H. & Hovenkamp P.H. (2003), Historical biogeography of Southeast Asia and the West Pacific or the generality of unrooted area networks as historical biogeographic hypotheses, Journal of Biogeography 30: 181-192.
- Welzen P.C. van (2003), The correct interpretation of Euonumus auriculatus Craib (Celastraceae) and Myladenia serrata Airy Shaw (Euphorbiaceae), Nat. Hist. Bull. Siam Soc. 50: 111-114.
- Welzen P.C. van (2003), A revision of the Malesian and Thai species of Sauropus (Euphorbiaceae: Phyllanthoideae), Blumea: Biodiversity, Evolution and Biogeography of Plants 48: 319-391.
- Welzen P.C. van (2003), Erismanthus obliquus, Homalanthus, Microstachys chamaelea. In: Lemmens R.H.M.J. & Bunyapraphatsara N. (red.), Plant Resources of South-East Asia, Medicinal and poisonous plants. Leiden: Backhuys Publishers. 239-242.
- Buijsen J.R.M., Welzen P.C. van & Ham R.W.J.M. van der (2003), A phylogenetic analysis of Harpullia (Sapindaceae) with notes on historical biogeography, Syst. Bot. 28: 106-117.
- Slik J.W.F., Keβler P.J.A. & Welzen P.C. van (2003), Macaranga and Mallotus species (Euphorbiaceae) as indicators for disturbance in the mixed lowland Dipterocarp forest of East Kalimantan (Indonesia), Ecological Indicators 2: 311-324.
- Stuppy W., Welzen P.C. van, Klinratana P. & Posa M.C.T. (1999), Revision of the genera Aleurites, Reutealis, and Vernicia (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 44: 73-98.
- Welzen P.C. van & Stuppy W. (1999), Phylogenetic considerations of Euphorbiaceae tribe Aleuritideae, Ann. Missouri Bot. Gard. 86: 894-903.
- Welzen P.C. van (1999), Sapindaceae. In: Sntisukl T. & Larsen K. (red.), Flora of Thailand 7(1): 169--250, pl. VII 2--4, pl. VIII.. Bangkok, Thailand: The Forest Herbarium. 169-250.
- Welzen P.C. van (1999), Indian Sapindaceae: Interesting topic for research?. In: Mathew P. & Sivadasan M. (red.), Diversity and Taxonomy of Tropical Flowering Plants.. Calicut, India: Mentor Books. 135-165.
- Welzen P.C. van (1999), Revision and phylogeny of subtribes Chrozophorinae and Doryxylinae (Euphorbiaceae) in Malesia and Thailand, Blumea: Biodiversity, Evolution and Biogeography of Plants 44: 411-436.
- Welzen P.C. van, Tyas K.N., Eviyarni & Gaerlan F.J.M. (1999), The Malesian species of Melanolepis (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 44(2): 437-446.
- Forster P.I. & Welzen P.C. van (1999), The Malesian species of Choriceras, Fontainea, and Petalostigma (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 44: 99-107.
- Welzen P.C. van (1998), Borneodendron, Chaetocarpus, Guioa, Harpullia, Ptychopyxis, Securinega, Tristiropsis. In: Sosef M.S.M., Hong L.T. & Prawirohatmodjo S. (red.), PROSEA 5(3): 112, 156, 157, 272-274, 282-284, 484, 485, 519, 520, 568-570. Timber trees: Lesser-known timbers.. Leiden: Backhuys Publishers.
- Welzen P.C. van (1998), Phylogenetic versus Linnean classifications. (summary lecture), Acta Bot. Neerl. 47: 262.
- Welzen P.C. van (1998) A checklist of the flowering plants and gymnosperms of Brunei Daressalam. Bespreking van: Coode M.J.E. (1998), Book review.. Kew Bull. 53: 757, 758.
- Welzen P.C. van (1998), Phylogenetic versus Linnean taxonomy, the continuing story, Taxon 47: 413-423.
- Kiew R. & Welzen P.C. van (1998), Codiaeum variegatum var. cavernicola var. nov. (Euphorbiaceae), the second Codiaeum from Borneo, Gard. Bull. Singapore 50: 31-34.
- Widuri R. & Welzen P.C. van (1998), A revision of the genus Cephalomappa (Euphorbiaceae) in Malesia, Reinwardtia 11: 153-184.
- Nguyen Nghia Thin, Vu Hoai Duc & Welzen P.C. van (1998), A revision of the Indochinese-Malesian genus Strophioblachia (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 43: 479-487.
- Esser H-J., Welzen P.C. van & Djarwaningsih T. (1998), A phylogenetic classification of the Malesian Hippomaneae (Euphorbiaceae), Syst. Bot. 22: 617-628.
- Welzen P.C. van (1998), Guioa sarcopterifructa (Sapindaceae): a new Australian species, Austrobaileya 5: 103-105.
- Welzen P.C. van (1998), A revision of the introduced species of Manihot (Euphorbiaceae) in Malesia, Rheedea 7: 77-85.
- Welzen P.C. van & Turner H. (1998), Vicariance and dispersal in Malesian Sapindaceae: General Patterns (summary lecture). Fourth International Flora Malesiana Symposium. Malaysia.: FRIM. [overig].
- Welzen P.C. van & Esser H-J. (1998), Phylogeny of the Malay species in the tribe Hippomaneae (Euphorbiaceae): added value for local floras. (summary lecture), Acta Bot. Neerl. 47: 261.
- Welzen P.C. van (1998), Revisions and phylogenies of Malesian Euphorbiaceae: Subtribe Lasiococcinae (Homonoia, Lasiococca, Spathiostemon) and Clonostylis, Ricinus, and Wetria, Blumea: Biodiversity, Evolution and Biogeography of Plants 43: 131-164.
- Welzen P.C. van (1998), Analytical key to the genera of Thai Euphorbiaceae, Thai For. Bull. 26: 1-17.
- Stuppy W. & Welzen P.C. van (1998), Phylogeny of the subtribe Aleuritineae (Euphorbiaceae). (summary lecture), Acta Bot. Neerl. 47: 260.