Abstract: A turbine rotor has composite ceramic blades each having a bulb-shaped root with planar flanks which define an angle of convergence between them not exceeding ten degrees, and by which the root is held in a dovetail section socket in the periphery of the rotor disc by means of wedge-shaped members also disposed in the socket on opposite sides of the root. Each wedge-shaped member is part of an element including a platform which is disposed adjacent the curved portion of the blade radially outwards of the socket and which is joined to the wedge-shaped member by an integral strut. The platforms of all of the elements extend in a circumferential direction and combine to define a continuous ring forming part of the inner boundary of the gas flow path through the turbine.