Scotland has some super plant fossil plant. A number of the sites are protected and Scotland also has a good code of conduct for collecting fossils. See links below:
Rhynie - http://www.abdn.ac.uk/rhynie/
Scottish Fossils (book by Professor Nigel Trewin) - http://www.edinburghgeolsoc.org/eg_pdfs/issue54_00_fullissue.pdf see pages 27 & 28 for a review of the book
I've posted a microscope image of one I found this year, likely to be Devonian in age. I will try to post some others later!