Roll half of pastry to 1/8-inch thickness on a lightly floured surface; fit into a 9-inch pie plate. Set aside.
Wash and mash muscadines. Separate hulls from pulp; set hulls aside. Strain pulp, reserving juice; discard pulp and seeds. Combine juice and hulls in a heavy saucepan; cover and cook over low heat 20 minutes or until hulls are tender. Cool.
Combine hull mixture, lemon juice, flour, and sugar; mix well. Pour into prepared pastry shell; dot with butter.
inch thickness; cut into 3/4-inchwide strips, and arrange in a lattice fashion over filling. Trim edges; seal and flute. Bake at 400° for 10 minutes. Reduce heat to 375°, and bake 25 to 30 additional minutes.