Science Reference Center is a comprehensive research database that provides easy access to a multitude of full text science-oriented content. This database contains full text for nearly 640 science encyclopedias, reference books, periodicals, etc. Topics covered include: biology, chemistry, earth & space science, environmental science, health & medicine, history of science, life science, physics, science & society, science as inquiry, scientists, technology and wildlife.
Links and lots of information about biology, bio-diversity, plant biology, evolution, microbiology, and much more.
“Originally founded as a Web site for curious people, the award-winning company now offers clear and fascinating content.” Categories include computers, science, money, people, and lots more. This site is good for browsing but also has a strong index.
All about plants; this site is maintained by the U.S. Dept. of Agriculture, National Resources Conservation Service.