There has been an increasing demand for applications to support multicast communication in the mobile ad hoc networks. One of the primary concerns in the multicast communication is the feasible design of the multicast ad hoc routing protocols. Conventionally, the design of the multicast routing protocols can be categorized into the tree-based and the mesh-based schemes. These two types of protocols have their own strength and weakness under different networking scenarios. In this paper, a Power-Controlled Hybrid Multicast Routing (PCHMR) protocol is proposed, which consists of both the tree-based and the mesh-based structures. The route determination scheme of the PCHMR algorithm not only relies on the hop counts but also on the received power strength of the neighborhood nodes. Moreover, the route determination thresholds are adaptive to the mean and the variations of the received power. The proposed PCHMR algorithm is suitable for the dynamically changing network topologies, especially for the group mobility scenario. Different signal propagation models are utilized in the simulations to evaluate the effectiveness of the PCHMR protocol.