The Rhytismatales, commonly referred to as ‘tar-spot’ fungi, are facultatively biotrophic, necrotrophic or saprobic on leaves and bark, sometimes also fruits, seeds and wood, frequently beginning as symptomless endobionts, later fruiting when the substratum has died. Those causing economic damage as needle diseases in conifers are the least poorly known. Their positive value as nutrient recyclers, and their possible protective role as endobionts is almost completely unevaluated. Most records are from the north temperate to subarctic zones, or from southern South America and Australasia; many collections are on conifers, the Ericaceae and Gramineae. Some species are widespread and plurivorous; others highly host-specific and limited in distribution.