The Morris chair is the father of all reclining chairs. It was first produced in England by the William Morris Company around 1866. Morris' chair was later copied by furniture makers like Gustav Stickley and, due to its Mission-style design, became a popular choice for homes during the Arts and Crafts Movement in the early 1900s. Morris chairs are still being manufactured today and because of their clean lines are at home in almost any décor.
Research the Morris chair. Before you can determine if your Morris-style recliner is an original Morris chair manufactured by the William Morris Company, you need to learn as much as possible about it. Books on the topic like "Arts and Crafts (DK Collector's Guide)" by Judith Miller are a good place to start. Websites like The William Morris Society and the Arts and Crafts Society that are devoted to William Morris and the Arts and Crafts Movement can also be helpful. Dealers and collectors of Mission-era furniture are also good sources of information.
Inspect the chair. Original Morris chairs were made of dark stained oak. Although Morris chairs are most often associated with the Arts and Crafts movement and its interest in building sturdy, clean-lined furniture, original Morris chairs had a more Victorian influence. They had cushioned arm rests, a back that reclined and decorative spindles. In early Morris chairs, the cushions were sewn into the chair seat and upholstered in wool tapestry, the patterns often designed by Morris himself. Unlike the decorative spindles seen in the original chair, later designs, like those built by Gustav Stickley, were heavier and simpler with wide arms shaped like paddles and square slats supporting the back and arms. The arms were not upholstered and the cushions were removable and often leather. A Stickley Morris-style chair will have Stickley's decal or paper label identifying the manufacturer.
Consult an expert. The only way to tell conclusively that your chair is an original is to have it appraised by an expert on the subject. You can find certified appraisers through professional appraisal organizations like the American Society of Appraisers.