About Plants of the World Online

Welcome to Plants of the World Online (POWO) which is an international collaborative programme that has as a primary aim to make available digitized data of the world’s flora gathered from the past 250 years of botanical exploration and research. POWO also aims to make freely available electronic data created by different projects but that no longer have an online presence or where data was never made available externally. It delivers information on the taxonomy, identification, images, distribution, traits, threat status, molecular phylogenies and uses of vascular plants worldwide. The data are sourced from the Royal Botanic Gardens, Kew as well as its partners and collaborators who generously contribute data and make it openly accessible on POWO.

Launched in March 2017 by the Royal Botanic Gardens, Kew, with an initial focus on tropical African Floras was made possible through the generous support of our benefactors, Michel and Hélène David-Weill. POWO’s aim is to empower and inform citizens, policy makers, conservationists, horticulturalists, farmers, gardeners and plant enthusiasts globally. The codebase is open source and Kew supports existing partner networks to set up their own portals, creating a distributed network of botanical data hubs.

All data incorporated into POWO are attached to the currently accepted name from the WCVP names backbone. Descriptive data published in the past one hundred years are digitized under the name used at the time. Because of continuous research and better insights into how plants are related to each other, plant names have had to be changed and therefore the original name under which the data was published may differ from the name under which it is currently displayed on POWO. Full synonymy is provided in POWO, so it is easy to find the data under any name you search for as well as indicating with each descriptive element the original name under which the data were published.

In addition, a key function of POWO is to ensure that relevant data can be harvested for research purposes and to be incorporated by the World Flora Online (WFO) portal enabling the POWO data providers to support the Global Strategy for Plant Conservation (GSPC) Target 1 2020. The latest version of the WCVP names and geography backbone can be downloaded from the tab “DATA” or the Research Repository.

Plant names backbone and maps

POWO uses WCVP as the names backbone which is also used by GBIF, CoL and WFO and many others, though they may be using older version so it is essential to check which version of WCVP they use. The names and distribution data are updated every Monday from WCVP data harvested the previous Wednesday. The maps are generated from the level 3 TDWG geographical codes in the WCVP database and are also refreshed every Monday on POWO.

The names backbone WCVP is primarily a list of all species of vascular plants. Generic circumscriptions generally follow published global generic accounts. For more information, please read the About WCVP pages.

Evidence for acceptance or synonymy of names are given in the form of references which are cited under the bibliography, citing references that accept the name are under the heading “Accepted by” and those that synonymise the name are under the heading “Not accepted by”. Evidence for presence in a particular botanical country can also be found in the bibliography and specifically under the heading “WCVP Backbone Distributions “. In principle the latest published species taxonomy is followed unless reviewers tell us otherwise. It is important to stress that the references can only be added to names used in the cited publication and therefore when a genus is sunk only the genus and the type species may have references as the other names are not mentioned in the paper that sinks the genus. The reference may also be under one of the homotypic names, it is therefore important to consider all references under the accepted name, its synonyms, the genus and the synonyms of the genus to get the full picture of the evidence for a particular species taxonomy.

Unplaced names are names that cannot be accepted, nor can they be put into synonymy. This may be because the name is not validly published, or it is a later homonym and therefore illegitimate or because the genus name is not accepted. A name can also be unplaced because it cannot be put into synonymy which may be because no correct name is available in an accepted genus, this may also be because no type material is known to exist and therefore it cannot be established to which species concept the name belongs or the type material may be insufficient to establish a clear identity or it may not have been studied by experts in the group and therefore no published synonymy exists.

Autonyms are currently only included for plant families that have been peer reviewed and which are also available on the WCSP website https://wcsp.science.kew.org/ as well as some in Asteraceae, Ferns and Fabaceae. We hope to add all autonyms when the geography has been completed.


It is important to stress that POWO is a data provider and no data are compiled or edited within POWO itself but come from a diverse spectrum of contributors both internally from Kew gardens as well as externally from partners and contributors. The central premise is to make historic published data available as it was published, it is not the intention to edit those published data nor to add to them. It is therefore very important to look at each of the data elements provided within the context of when and where they were published. Any changes made to the contributing databases will feed through to POWO when those datasets are refreshed.

We aim to incorporate the latest published taxonomy but sometimes papers are overlooked, in which case, please let us know. Also, sometimes changes are not made as we feel more evidence is needed to prevent changing the taxonomy and then at a later point having to change it again which can be very disruptive for users. Changes that affect horticulture are often discussed and agreed with the Royal Horticultural Society (RHS) which may involve lengthy consultations with the users of those names.

Newly published names are added from IPNI at the beginning of each year into the names backbone, WCVP. They are then edited and therefore take some months to become visible on the POWO website, so if a name you recently published is missing, please check the IPNI website and if the name is present then it will be visible on POWO soon, if it is not on IPNI, then please register the name at IPNI Registration and it will then appear on POWO early the following year. New names are never added manually into POWO as that will inevitably lead to duplicates over time and duplication of effort.

POWO is a dynamic resource and content is added continuously from the contributing datasets and taxonomic decisions are made from peer reviewed, curated, authoritative sources where we can, but not in every case. POWO therefore should only be treated as advisory. Other, more authoritative lists may exist for particular regions or taxa though it is essential to compare like for like as many online resources are no longer updated and therefore the date on which the data was last updated should be checked, for POWO that is last Monday.

Identifiers ending with ‘-4’

Both POWO and the WCVP names backbone use the IPNI Life Sciences Identifier (LSID) as their ID’s and therefore only plant names that are also in the International Plant Names Index (IPNI) can be shown. Consequently, some scientific plant names featured in POWO but not present in IPNI will include an identifier that ends with ‘-4’ e.g. ‘2557526-4’.

Any name record from the World Checklist of Vascular Plants (WCVP) database which has not been reconciled with a corresponding name record from the International Plant Name Index (IPNI) database, will include this temporary identifier ending in '-4'.

These temporary identifiers permit all WCVP name records to be included in POWO regardless of whether they have been reconciled with IPNI. They are not valid IPNI identifiers and therefore no external link from POWO to IPNI is provided for these names.

The IPNI and WCVP databases are continuously being reconciled and when a new match is discovered the temporary identifier is replaced in POWO with the genuine IPNI identifier.