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, 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.
- 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: Biodiversity, Evolution and Biogeography of Plants 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.
- Stoops E. & Welzen P.C. van (2013), A revision of Ptychopyxis (Euphorbiaceae) in Southeast Asia, Nordic Journal of Botany 31: 94-112.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- Welzen P.C. van & Forster P.I. (2011), Picrodendraceae. In: Nooteboom H.P. (red.), Flora Malesiana. Leiden: Foundation Flora Malesiana.
- 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), Floristic regions in Thailand, now and in the future, 15th Flora of Thailand Meeting (7-11 Nov. Chiang Mai): 20.. .
- Chantarasuwan B., Berg C.C. & Welzen P.C. van (2011), A revision of Ficus subsection Urostigma (Moraceae), 15th Flora of Thailand Meeting : .
- 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.
- 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.
- 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].
- 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].
- 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 : .
- 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 : .
- 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 : .
- 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.
- Welzen P.C. van, Hovenkamp P.H. & Turner H. (2011), Pathways through Malesia. [overig].
- 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, 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.
- Sirichamorn Y., Adema F.A.C.B. & Welzen P.C. van (2010), The genera Aganope, Derris and Paraderris (Fabaceae) in Thailand. [overig].
- Welzen P.C. van & Raes N. (2010), The floristic position of Java. [overig].
- Welzen P.C. van (2010), Leeaceae, Flora of Thailand 10(2): 209-230.
- Hou D. & Welzen P.C. van (2010), Celastraceae, Flora of Thailand 10(2): 141-198.
- Welzen P.C. van (2010), Revision of the Asian genus Koilodepas (Euphorbiaceae), Ann. Missouri Bot. Gard. 97: 218-234.
- 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.
- 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.
- 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 & 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.
- 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].
- Chantarasuwan B., Berg C.C. & Welzen P.C. van (2010), Taxonomy and Systematics of Ficus subsection Urostigma (Moraceae). [overig].
- Barker C. & Welzen P.C. van (2010), Flueggia (Euphorbiaceae s.l. or Phyllantyhaceae) in Malesia, Syst. Bot. 35: 541-551.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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., 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, 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 (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 & Bulalacao L.J. (2007), The genus Alchornea (Euphorbiaceae) in the Malay Archipelago and Thailand, Systematic Botany 32: 803-818.
- 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.
- Welzen P.C. van & Sierra S.E.C. (2006), The Mallotus wrayi complex (Euphorbiaceae), Blumea: Biodiversity, Evolution and Biogeography of Plants 51: 373-388.
- 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.
- 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.
- Welzen P.C. van & Phonsena P. (2005), Lepisanthes amoena (Hassk.) Leenh. (Sapindaceae), a new record for Thailand, Thai For. Bull. 32: 170-172.
- Welzen P.C. van (2005), A new combination in Meliosma (Sabiaceae), Thai For. Bull. 32: 168-169.
- 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 & 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.
- 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.
- 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.
- 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.
- 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 & Phonsena P. (2004), Lepisanthes amoena (Hassk.) Leenh. (Sappindaceae), a new record for Thailand, Thai For. Bull. 32: 170-172.
- 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.
- 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 (2003), The correct interpretation of Euonumus auriculatus Craib (Celastraceae) and Myladenia serrata Airy Shaw (Euphorbiaceae), Nat. Hist. Bull. Siam Soc. 50: 111-114.
- 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.
- 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), 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.
- 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.
- 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 (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 (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, 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.
- 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.
- 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.
- 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), Phylogenetic versus Linnean taxonomy, the continuing story, Taxon 47: 413-423.
- 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) 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), Analytical key to the genera of Thai Euphorbiaceae, Thai For. Bull. 26: 1-17.
- Welzen P.C. van (1998), Guioa sarcopterifructa (Sapindaceae): a new Australian species, Austrobaileya 5: 103-105.
- 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 (1998), Phylogenetic versus Linnean classifications. (summary lecture), Acta Bot. Neerl. 47: 262.
- Stuppy W. & Welzen P.C. van (1998), Phylogeny of the subtribe Aleuritineae (Euphorbiaceae). (summary lecture), Acta Bot. Neerl. 47: 260.
- 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.
- 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), A revision of the introduced species of Manihot (Euphorbiaceae) in Malesia, Rheedea 7: 77-85.
- Widuri R. & Welzen P.C. van (1998), A revision of the genus Cephalomappa (Euphorbiaceae) in Malesia, Reinwardtia 11: 153-184.