This post is a long time coming. I've been trying to pull together a list of resources for a couple of weeks now but with vacations and kids home for the summer it just hasn't happened until now!
Another reason it took so long to post... there are just SO MANY resources out there I didn't know where to start. Wildflowers vary by country and then region within a country so the amount of books to look through are too numerous to count! But identifying wildflowers is fun and rewarding so I believe it's important to find a book (or app or website) that works for you. Since we live in North America, I've focused on books from our area but know that a lot of these publishing companies publish books for various regions. So check around and see if you can find something for your area. And if you have a favorite wildflower book, let us know!