Abstract A description is provided for Lophodermium juniperinum . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Reported from many species of Juniperus , especially J . communis . Also reported from Chamaecyparis spp. and Libocedrus decurrens [Calocedrus decurrens] . DISEASE: The pathogenicity of L. juniperinum has not been clearly established. Various authors (e.g. Peace (42, 155), Lanier (58, 2948), Parmelee (62, 4192)) have included it in lists of parasites of Juniperus , but none presented any firm evidence of pathogenicity. However, Darker (12, 254) could find no reason to suspect that L. juniperinum was other than a saprophyte. At least in Scotland, the ascomata develop on needles still attached to the tree, and mature between May and July. GEOGRAPHICAL DISTRIBUTION: Very widely distributed in temperate regions. Recorded from Austria, Belgium, Canada, Czechoslovakia, Denmark, Eire, Finland, France, Germany, Hungary, Iceland, Italy, Norway, Poland, Roumania, Sweden, Switzerland, UK and USA. TRANSMISSION: Unknown. Similar fungi have air-dispersed spores directly infecting host leaves.