Plants

Botany Encyclopedia of Plants
Provides general description of plants, various methods of cultivation, soil and temperature requirements, pruning.
http://www.botany.com/

Lapshin's Succulent Encyclopedia
Photos of succulents of numerous families.
http://www.lapshin.org/succulent/

Metropolitan Plant Encyclopedia
Consists of a series of pages on the plants of the New York metropolitan region.
http://www.bbg.org/sci/nymf/encyclopedia/

A Modern Herbal
Index of more than 800 varieties of herbs and plants, word search of the text, recipes, and an index of poisonous plants.
http://www.botanical.com/botanical/mgmh/mgmh.html

Virtual Palm Encyclopedia
History, horticulture, pests and diseases, conservation, photographs, and references.
http://www.plantapalm.com/vpe/vpe_index.htm