PLANT ID RESOURCES
https://www.minnesotawildflowers.info/ is a great source of identification information for both native and invasive species. Although it's specific to Minnesota, it includes most species found in Wisconsin.
The GLEDN app includes pictures of each species that are available offline.
https://www.inaturalist.org/ and the associated smartphone app can help solve identification questions by allowing others to view your reports and confirm or contest your identification.
Invasive Plants of the Upper Midwest: An Illustrated Guide to Their Identification and Control by Elizabeth J. Czarapata is a highly recommended book for those interested in invasive plants. It is available for purchase online from various retailers.
Dutchman's breeches is a native spring wildflower.