Bryophyte Marchantia polymorpha L. produces C22 very-long-chain polyunsaturated fatty acid (VLCPUFA). Thus far, no enzyme that mediates elongation of C20 VLCPUFAs has been identified in land plants. Here, we report the isolation and characterization of the gene MpELO2, which encodes an ELO-like fatty acid elongase in M. polymorpha. Heterologous expression in yeast demonstrated that MpELO2 encodes delta5-elongase, which mediates elongation of arachidonic (20:4) and eicosapentaenoic acids (20:5). Phylogenetic and gene structural analysis indicated that the MpELO2 gene is closely related to bryophyte Delta6-elongase genes for C18 fatty acid elongation and diverged from them by local gene duplication.