Well, the book I had in mind was published in 1922 so I'm thinking it's not much of a bestseller anymore. It's called "How to Know the Wild Flowers" by Mrs. William Starr Dana. There are people selling it used on Amazon for anywhere from $72-$185 depending on condition. My copy has $30 on the inside and I think the antique store was having a sale. I never pay full price at antique stores - you gotta deal! There are cheaper versions that are newer and a softcover version, as well, that's not so pricey. The first copyright was in 1893 followed by others in 1895, 1900, and 1921. I have the new revised version featuring all new color plates!
It's a pretty nice book, not only in how she describes the flowers, but how she talks about where they grow, what other plants they're commonly found with, and common uses of the plant.