Thanks Kilgore trout. It would have been a lot easier though if I had entered 4 down correctly. I am now feeling slightly paranoid and will have to carefully check every entry again - but that will be preferable to searching for non existing plants and rivers!!! I suppose the difficulty of this crossword is that the numbers create so many possible permutations for missing answers that you don't realise you have made a mistake until you actually cold solve the clues.