+1 on the Stensaas flora book.
"Lichens of the North Woods" by Joe Walewski. This is a field guide book with color photos.
"Birds of Minnesota Field Guide" by Stan Tekiela. It has color photos.
Here's an offbeat recommendation, not strictly limited to BWCA/Quetico wildlife: "A Field Guide to Animal Tracks" by Olaus J. Murie. It has drawings of tracks and scat, including dimensions.
Here is a link to printed material including photographs about pictographs:
Pictographs