NOVELTY - The plate has two surfaces and a set of header openings (40, 40`, 42, 46`, 48), where a flow field is formed on one of the surfaces of the plate. The flow field includes an inlet feed region and an outlet region, where the inlet region and the outlet region have feed area channels to provide fluid communication with the header opening. An elongated sealing member (100) is formed on the plate to cooperate with a seal assembly (200) to form a fluid tight seal, where the seal is formed from an elastomer and the sealing member includes two lateral side spaced apart from each other.    USE - Plate for use in a fuel cell stack (claimed) i.e. proton exchange membrane fuel cell stack, for combining fuel such as hydrogen and oxygen to produce electricity, in fuel cell system that is utilized as a power source in vehicles for replacement for internal combustion engine, stationary electric power plants in building and residence, portable power in video camera and computer, and for providing power for an electric motor. Can also be used for natural gas, methanol, gasoline, and coal-derived synthetic fuels.    ADVANTAGE - The sealing member does not require additional surface finish treatment such as applying a sealing material, and is effective to form and maintain a fluid tight seal over a wider range of dimensional variation within the fuel cell stack, thus minimizing the number of critical tolerances that must be maintained in the different components of the fuel cell stack, and hence minimizing the manufacturing cost of the fuel cell plate. The seal assembly structure militates against a leakage of fluids from the fuel cell system, and facilitates maintenance of a desired velocity of the reactant flow in the fuel cell system.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a fuel cell stack comprising a spacer.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded perspective view of a proton exchange membrane fuel cell stack.    Fuel cell stack (10)    Electricity producing cells (12, 14)    Unitized electrode assembly (16, 18)    Bipolar plate assembly (20)    Monopolar end plate assemblies (22, 24)    Header openings (40, 40` 42 46` 48)    Sealing member (100)    Seal assembly (200)    Modified seal assembly (300)