- USDA Plants Database - Provides a single source of standardized information about plants
- Gymnosperm Database - Database of conifers and other gymnosperms
- Online Vegetation and Plant Distribution Maps - includes maps from all over the world.
- Glossary of Botanical Terms - interactive glossary of terms relating to botany, gardening, horticulture and
- Flowerbase - Database of more than 7000 flowers.
- Southern California Wildflowers - by Dr. Barbara J. Collins, California Lutheran University