the internet because often this information just repeats over and over the same details
YES! Books are still important resources. This one looks amazing! I have a few English reference books of wild foods that I still use here... whilst they are not 'wild' in the truest sense there are places where we can find hawthorn, yarrow, quince - and of course herbs in cultivated gardens, so they are still useful!
RE: The Wild World: Studying and Documenting Wild Plants.