Ask the fox herself for help. She will show you the exact images of the flowers you need to collect. Just memorize them, go to the meadow and bring back the same ones.
If it still doesn't work even though you're sure you did everything correctly and have literally the flowers from her guide in your backpack - please come back, report the bug to us and send your save file.
Though I think it should work, this quest was tested pretty well. If you do figure it out, please let us know too so we don't worry =)