Philadelphia Botanical Club
- Society presents its long history, meetings and field trips, herbarium, journal, and officers, with a membership form.
- http://www.acnatsci.org/hosted/botany_club/

Botanical Society of the British Isles
- Founded in 1836, it is the major source of information on the status and distribution of British and Irish flowering plants and ferns.
- http://www.bsbi.org.uk/

International Association for Plant Taxonomy
- Carries out projects of interest to systematists, especially those that require international cooperation.
- http://www.bgbm.fu-berlin.de/iapt/

American Bryological and Lichenological Society (ABLS)
- An organization devoted to the scientific study of all aspects of the biology of bryophytes and lichen-forming fungi.
- http://www.unomaha.edu/~abls/

American Society of Plant Biologists (ASPB)
- To promote the growth and development of plant biology, to encourage and publish research in plant biology, and to promote the interests and growth of plant scientists in general
- http://www.aspb.org

California Botanical Society
- Systematics, ecology, evolution, and natural history of the plants of California and adjacent western North America. Publisher of the journal Madroño.
- http://www.calbotsoc.org/

Botanical Society of America
- Promoting research and teaching in all fields of plant biology to facilitate cooperation among plant scientists worldwide and to disseminate knowledge of plants, algae and fungi. Links to the American Journal of Botany, Plant Science Bulletin, national m
- http://www.botany.org

Australian Systematic Botany Society
- homepage for Australian systematic botany society, news, conferences and publications.
- http://www.anbg.gov.au/asbs/