ACKNOWLEDGEMENTS

The key and all plant images are ©2002-2008 Gary Fewless. The Wisconsin distribution maps were produced by the UW-Madison Herbarium and are based on the voucher specimens held by the following herbaria: UW-Madison (WIS), UW-Green Bay, UW-Stevens Point, and UW-Superior; Milwaukee Public Museum (MIL); Fort McCoy; Illinois Natural History Survey; SE Wisconsin Regional Planning Commission; WIS-DNR; Morton Arboretum (MOR); and various other Wisconsin collections. The distributions shown are based primarily on locations for which a herbarium voucher is known. It is likely that current and future botanists will improve the record of distributions.

As is the case with most keys, this one relies heavily on the works of previous authors. In the case of some difficult groups of species the key is directly modeled after the treatments in the Flora of North America, Vol. 2, which has become the most widely used standard for the treatment of pteridophytes in North America and is highly recommended. Those considering the purchase of this publication may examine the contents on the Flora of North America web site, including keys, text, range maps and figures.