We propose a novel MAC layer multicast scheme for the IEEE 802.11s based multi-hop WLAN mesh networks, where a layer 2 unicast routing protocol (named HWMP - Hybrid Wireless Mesh Protocol) is defined. We were motivated by the fact that no multicasting algorithm has been defined in the draft of 802.11s standard. In this paper, we present the two multicasting schemes: Layer2Multicast-Simple (L2M-S) and Layer2Multicast-Enhanced (L2M-E). In the L2M-S scheme, we simply utilize tree-based routing information created and maintained by the HWMP for the purpose of multicasting so no additional path maintenance overhead needs to be generated. Second, in the L2M-E scheme, a distributed tree optimization process is additionally introduced to further improve the performance of the MAC layer multi-hop multicasting. Simulation results using the QualNet simulator show that our protocols can reduce the data transmission overhead and improve the network throughput.