Textbooks:

Fassett, Norman C. 1976. Spring Flora of Wisconsin: a manual of plants growing without cultivation and flowering before June 15. 4th ed. Revised and enlarged by Olive S. Thomson. The University of Wisconsin Press. Madison. 413 pp.

Recommended books:

Black, M.R. and E.J. Judziewicz. 2008. Wildflowers of Wisconsin and the Upper Midwest. UW Stevens Point Press - just published guide specific to Wisconsin; nicely illustrated with descriptions, diagnostic features, and biogeographical distributions

Harris, J. G. and M. W. Harris. 1994. Plant Identification Terminology. An Illustrated Glossary. Spring Lake Publ. Spring Lake, Utah.

Newcomb, L. 1977. Newcomb's Wildflower Guide. Little, Brown & Co. - nicely illustrated wildflower guide for NE and N Central USA.

Barnes, B.V. and W.H. Wagner, Jr. 2003. Michigan Trees: A Guide to the Trees of the Great Lakes Region. University of Michigan Press - authoratative book on trees (and some shrubs) of this area

Petrides, G. A. 1986. Peterson Field Guides: Trees and Shrubs. Houghton Mifflin Co. - superb guide to all woody plants (trees, shrubs, vines) in NE and N Central USA and adjacent parts of Canada.

Gleason, H. A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada (2nd edition). New York Bot. Gard. (copies available in laboratory; but you may wish to purchase this if you are continuing in the field).

You may also wish to purchase a hand lens and dissecting kit for use in the lab - all are available at the University Bookstore.