Seiridium is a genus of plant pathogens in the family Sporocadaceae.

[1] The genus Lepteutypa is teleomorphic (reproducing sexually) and the corresponding anamorphic name, used to describe the asexual form, is Seiridium (formerly Coryneum).

On the other hand, no sexual stage of species Seiridium cardinale is known, so that is its only name.

[2][3] Seiridium cardinale is important to gardeners and foresters as they cause the devastating Cypress canker disease on Cupressus, Thuja, and related conifers in Northern Europe, America, Australia,[4] and New Zealand.

[5][6] Seiridium cardinale is from California and was introduced to Europe around the 1930s, probably from infected nursery stock.