Preheat Oven to 375 degrees. Mix flour and brown sugar together. Line a 23 cm pie plate with pastry.Sprinkle a third of the flour, sugar mixture over the crust. Arrange a layer of rhubarb, scatter lemon slices over it, sprinkle with sugar mixture. Repeat once or twice until all ingredients are used. Cover with a lattice crust(preferr=able, as this is a juicy pie) and bake for 50-60 minutes. This is from Cookery AS It Should Be Cook Book,from 19 century America;sane,sober and delicious. Good Luck and Enjoy Joni in S.Jersey