The Division of Botany recommends the following to those wishing to pursue an interest in botany.
100 Uses for an Herbarium (Well at Least 72) [PDF 56K]
by Vicki Funk, U.S. National Herbarium, Smithsonian Institution
Angiosperm Phylogeny Website
http://www.mobot.org/MOBOT/research/APweb/
The Family of Flowering Plants
http://www.biologie.uni-hamburg.de/b-online/delta/angio/
Flora Malesiana
http://www.nationaalherbarium.nl/rhb/malesia.htm#flora%20malesiana
Flora Mesoamericana
http://www.mobot.org/MOBOT/fm/
Flora Neotropica
http://www.nybg.org/bsci/ofn/ofn.html
Flora of North America
http://flora.huh.harvard.edu/fna/
Harvard University Herbaria
http://www.huh.harvard.edu
The International Plant Names Index
http://www.ipni.org/index.html
Missouri Botanical Garden
http://www.mobot.org/MOBOT/research/
Natural Science Collections Alliance
http://www.nscalliance.org/
The New York Botanical Garden
http://sciweb.nybg.org/science2/
Phylocode
http://www.ohio.edu/phylocode/
University of Connecticut Herbarium (CONN)
http://bgbaseserver.eeb.uconn.edu/
W3 Tropicos (database)
http://www.tropicos.org/
American Society of Plant Taxonomists
http://www.sysbot.org/
Botanical Society of America
http://www.botany.org/
Connecticut Botanical Society
http://www.ct-botanical-society.org/
Society for the Preservation of Natural History Collections
http://www.spnhc.org/