Plant Information Online offers a collection of databases of interest to plant and gardening enthusiasts and students, as well as professional botanists, horticulturists, and researchers. Some of the databases have been available in print (various titles) since 1979 and online through paid subscription since 1997. The whole site is now available free to the general public.

Plant Information Online provides access to:

• Current Plant and Seed Sources for more than 80,000 plants (largest listing of cultivated plants in North America!) from approximately 1,000 North American firms that will ship plants.
• Contact information and links (where available) for more than 2,700 North American retail and wholesale seed and nursery firms that ship plants.
• Bibliographic details for over 415,000 images of more than 150,000 wild and cultivated plants from around the world in botanical and horticultural books and magazines from 1982 to the present.
  
  Plant Information Online is designed for ease of use. It offers cross-referencing of plant names and powerful search functionality.