Depending on size of phyllo sheets, you may have fewer than 10 left at the end. Halve sheets if necessary to give 10 layers. Beat egg whites until stiff and beat sugar in gradually. Fold in nuts and rose water. Butter top of phyllo square and place a tablespoonful of nut mixture in the centre. Gently squeeze into a lily shape, with four corners of square as petals and filling in centre. Place in a buttered 25 x 33 cm (10 x 13 inch) baking dish. Repeat with remaining ingredients, placing finished pastries close together in dish. Bake in moderate oven for 30 minutes, reduce to slow and cook for further 15 minutes. Meanwhile dissolve sugar in water over heat, add lemon juice and orange water and bring to the boil. Boil for 15 minutes, stir in rose water and cool. Spoon cool thick syrup over hot pastries. Leave until cool and sprinkle pistachio nuts in centres of pastries if desired. Note: If you are not used to working with phyllo pastry, then it is advisable to fill and shape the first lot of buttered squares before going onto the nest lot. The butter firms fairly quickly and it could be difficult to shape the pastries if the buttered sheets are left for a time.