Includes some design calculations. The - There are over 1400 gardening links in 56 categories. I have tried to keep this list friendly to the Home Gardener. With Lichens - Contains a handy tool for identifying and explaining characteristics of lichens. For casual users Lichen Land Lite provides pictures and explanations of lichen features.
More advanced users can use the professional edition which provides more options for identification.
From Oregon State University. Virtual Orchard - a dedicated site for the dissemination of information over the Internet on all aspects of sustainable apple production. The - This basic but nicely organized site offers a vast amount of technical information about flowering plants, some with illustrations. From habit and leaf form to reproductive type and taxonomy, you can find it here. Interesting and easy to navigate.