Abstract: A seating unit comprising a main support having a pair of spaced apart side supports connected by transverse cross beams and a seat subassembly, including an internal frame with back cushion and seat cushion support portions secured on the main support by a concealed mounting means. The concealed mounting means is characterized by a pair of spaced apart upper tenon mounting mortises located internally on the main support. A pair of spaced apart upper tenons are secured on the back cushion support portion and located to be positioned in the upper mortises when the seating unit is in an assembly condition. A pair of spaced apart lower tenon mounting mortises are located internally on the main support. A pair of spaced apart lower tenons are secured on the seat cushion support portion and located to be positioned on the lower tenon mounting mortises when the seating unit is it in an assembled condition. Concealed threaded fastening devices are used to secure each of the tenons in its respective mortise.