It’s the creation of one Jill Bliss, a San Francisco resident and very talented artist.
I picked one up at the University of Washington Bookstore near the beginning of this summer. It’s beautiful! It has a very hand-crafted look and lovely illustrations in a polished, professional package. It has gridded and blank pages, each adorned with a different California flower.
It seems to be sold out everywhere, but it’s published by Chronicle Books, so if it reprints you might be able to find it there.