One of my favorite floras is a heavy book popularly called "The Jepson". Originally published in 1993, it is the work of several hundred authors and covers thousands of plant species in California. Species illustrations are abundant and superb. I first purchased the book for a course in systematic botany as an undergrad at UC Santa Cruz. My biological interests were mostly in the ocean at this time, but this was an interesting course that broadened my horizons. In 2012, a new hard copy edition of the Jepson Manual has become available. The new edition is accompanied by an on-line version of the flora that contains keys, maps, and taxon descriptions.
Herbaria are increasingly adding data and images of plant specimens on line. Such information should aid in studies of taxonomy, biogeography, natural history and ecology. Here are a few links to famous herbaria or regional consortia that enable access to data on these specimens.
- The Tropicos database of the Missouri Botanical Garden
- Smithsonian Institution collections
For those interested in the flora of the Pacific Northwest, a number of resources are available. First, Eugene Kozloff has a 2005 book entitled "Plants of Western Oregon, Washington & British Columbia". It has keys and a number of attractive color photographs. An older and comprehensive account of the flora in the region can be found in the 5 volume set "Vascular Plants of the Pacific Northwest" by C. Leo Hitchcock and colleagues. Another attractive field guide book is "Wildflowers of the Pacific Northwest" by Mark Turner and Phyllis Gustafson. The book is accompanied by a website of beautiful photographs. For information on the Oregon flora, including maps of species distributions and a checklist of vascular plants for the whole state, visit the Oregon Flora Project.