The following is a repository of resources to aid participants. Always use reliable sources in writing articles, and remember to cite them. Wikipedia policies and the Manual of Style should be consulted when in doubt.
{{Taxonbar}} bar at the bottom of taxon pages, displays shorthand links to biological and taxonomic databases based on the taxon's corresponding Wikidata entry
Generic citation templates including website, book, journal, thesis & dissertation, conferences reports, encyclopedia, and more
For angiosperm taxoboxes, we generally prefer APG IV, although exceptions may be made if more recent information is available.
Angiosperm Phylogeny Group (2003). An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society, 141, 399–436. available here : Available online. Out of date for some groups; see APG III or next reference for more up-to-date information based on research since 2003.
The TROPICOS database is searchable by species, and where this is available, will give the accepted classification, and the degree to which it is accepted. Also lists authors, synonyms and homonyms. Far from complete.
Vascular Plant Families – a systematic and alphabetical index of the non-flowering and the flowering plant families with the Cronquist system and the phylogenetic system of Judd et al. (2002) (i.e. APG)
USDA/NRCS PLANTS Database – Not complete, but nice. Resource for some PD images, although not all are PD. Common names listed may not be widely used, or widely used only in the USA. Not an especially good source for taxonomy (better is GRIN, below, and some of the others here).
IPNI, authors search Note that the author database is separate from the plant name databases: the author database is authoritative. The plant name databases are "as is" and should be used as a search aid (invaluable as such) rather than as any kind of authority.
Forestry Images a lot of images of plants released under creative commons 3.0.
IAPT Proposals and Disposals – Check on the status and history of a certain taxon name, e.g. when it was proposed for conservation or rejection, when the issue was resolved, etc.
Plantarium Database – a systematic index of the non-flowering and the flowering plant of Eurasia (mostly ex-USSR), more than 7700 illustrated taxa (in Latin and Russian). For English use Google Translator.
Wikipedia articles generally follow the Pteridophyte Phylogeny Group (PPG) system for ferns and lycophytes. As of March 2020[update], this is the 2016 PPG I system, supported by a very large number of pteridophyte researchers.
The orginal paper can be used down to genera (see PPG I (2016), "A community-derived classification for extant lycophytes and ferns", Journal of Systematics and Evolution, 54 (6): 563–603, doi:10.1111/jse.12229), although there have been some changes since that appear to have good support.
The only database that uses PPG and goes down to species appears to be World Ferns. It's regularly updated and the author has responded well to queries.
Unfortunately, Kew has decided to use the 2019 GLOVAP system for ferns. This is an extreme lumping system; for example the whole of PPG's subfamily Grammitidoideae with 33 genera and some 900 species is sunk into one huge genus Grammitis. Hence Plants of the World Online should not be used for lists of species, taxoboxes or article titles for ferns and lycophytes, although its position must, of course, be mentioned in the text. For a discussion of the "lumping" approach, see Schuettpelz, Eric; Rouhan, Germinal; Pryer, Kathleen M.; Rothfels, Carl J.; Prado, Jefferson; Sundue, Michael A.; Windham, Michael D.; Moran, Robbin C.; Smith, Alan R. (2018), "Are there too many fern genera?", Taxon, 67 (3): 473–480, doi:10.12705/673.1, ISSN1996-8175, and sources referenced there.
See the caveats on primary sources at WP:PRIMARY (although these journals sometimes run review articles, which are secondary sources, or an article starts by summarizing previous research).
Landcare Research New Zealand Limited. "Search Flora of New Zealand Series"(HTML). New Zealand Plant Names Database. Landcare Research Allan Herbarium and New Zealand Plant Names Database.
Pacific Island Ecosystems at Risk Lists many/most invasive non-natives including where they are found (includes Indian ocean islands but I don't think continental Australia, Japan, Korea, etc.)
Smithsonian herbarium archive, when you click on or hover over individual images, look at the header; the ones with "Usage Statement:CC0" at the bottom of the header are public domain, as Creative Commons zero means no rights reserved. As many other herbarium databases are copyrighted, this means the Smithsonian herbarium archive is a good source if you need to find an herbarium sample for uploading to Wikimedia Commons. (In February 2020, the Smithsonian placed 2.8 million images into CC0.[1])
Herbarium databases vary in their licensing from public domain to non-commercial-only. Non-commercial-only images are generally unacceptable for Wikipedia. A listing of the copyright licenses for various herbaria can be found here[2] and here[3].
Wild Flowers Worth Knowing. Don't rely on this for taxonomy (such as the scientific name of each species), but much of the historical and descriptive information is still applicable.
Fire Effects Information System for forest understory plants. Goes beyond responses to fire to also cover ecology, habitats, etc.
Wiki loves iNaturalist Experimental tool for locating photos of taxa in iNaturalist and determining their licensing status; can be used to upload suitable images to Commons.
ImageChecker tool can be used to locate plant articles tagged as needing images that may already have them.
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