Center for Plant Conservation
Collaborative organization dedicated to conserving and restoring the rare native plants of the United States. Includes information on collections of rare and endangered plants.

Forest Cover Types
Major timber cover type maps for the United States.

Heritage Forests Campaign
An alliance of conservationists, wildlife advocates, clergy, educators, scientists, and other Americans who are working together to uphold protection of the National Forests.

Botanical Society of America
Promoting research and teaching in all fields of plant biology to facilitate cooperation among plant scientists worldwide and to disseminate knowledge of plants, algae, and fungi. Links to the American Journal of Botany, Plant Science Bulletin, national meetings and symposia, and educational resources.