Fitter, Fitterr and Blamey is the best rucksack book. Rose is ok if you can be bothered to work laborously through the keys. It only covers British plants though and is not good on European plants that we are finding more and more as casuals or introductions. I use Fitter in the field, Rose at home for confirmation and the heavy Blamey and Grey-Wilson when all else fails. When "all else fails" fails I ask WAB and someone always knows
