- USDA National PLANTS Database and Projects -
- provides standardized information about the vascular plants, mosses, liverworts, hornworts, and lichens of the U.S. and its territories.
- Botany.com - includes an encyclopedia of flowers and plants indexed by botanical and common name as well as links to associations and societies.
- Great Plant Escape - elementary program for 4th and 5th grade students designed to introduce them to plant science and increase their understanding of how foods grow.
- Floridata - offers a photographic encyclopedia of flowers and landscape plants.
- Plants Magazine - featuring new rare and unusual garden plants from around the world.
- INVADERS Database System - comprehensive database of exotic plant names, distribution records, and regulatory information for the northwestern United States.
- HortiPlex - plant database containing images, gardening information, nomenclature data, and links.
- Plants for a Future - collection of leaflets about edible and other useful plants, including plants for lighting, fiber, soaps, oils, and information on permaculture and perennial plants.
- Plant Image Gallery - features a gallery of plants from all over the world.
- Grass Genera of the World - comprises an interactive identification and information retrieval system using the program Intkey, descriptions, illustrations, references, and other subsidiary material.