Erigeron maniopotamicus is a rare species of flowering plant in the family Asteraceae known by the common name Mad River fleabane. It is endemic to northwestern California, where it is known from only four locations in Humboldt and Trinity Counties.The Nature ConservancyCalifornia Native Plant Society Rare Plant ProfileCalflora taxon report, University of California, Erigeron maniopotamicus G.L. Nesom and T.W. Nelson Mad River fleabane
