Bioautographic assay on TLC plates was adopted to guide the fractionation of the Et2O extract of Homalia trichomanoides (Hedw.) B. S. G., which led to the isolation of the novel p-terphenyl derivative trichomanin (= 4,4''-dihydroxy-1,1':4',1''-terphenyl-2',3',5',6'-tetrayl tetrakis(phenylacetate);