Turtles Trading Post-  Keep America Beautiful- Set of 4 1969 FDC #1365-68 Fleetwood

The stamps are:   

#1365    Capitol with Azaleas & Tulips

#1366    Washington Monument; Potomac River and Daffodils

#1367    Poppies & Lupines Along Highway

#1368    Blooming Crab Apples Lining the Avenue

Cover is not sealed, no markings on reverse side