File:Coral Spot Fungus (Nectria cinnabarina) - geograph.org.uk - 1091903.jpg

English: Coral Spot Fungus (Nectria cinnabarina). At the place where this picture was taken, there is a line of tree stumps on the pavement; the fungi shown here were growing on the side of one of them.

This dense covering of pustules is an example of the so-called "conidial stage" of the fungus Nectria cinnabarina; its coral-pink colour explains the common name of Coral Spot Fungus.

This fungus occurs in dense groups on dead or dying wood - the twigs and branches of (usually) broad-leaved trees - and causes Coral-spot Disease; however, it is not a particularly strong parasite in itself, and its presence on a living plant probably indicates that its host was not in the best of condition to start with.

Another commonly-encountered phase of its life-cycle, the so-called "perithecial stage", is shown on the right-hand side of the following photo: 1018737. As with many similar fungal species, it was not realized at first that the two phases were really the same species, and they were originally assigned different scientific names (in this case, the pink conidial stage was named Tuberculina vulgaris). When subsequent research reveals them to be merely two different stages of the same species, one of the two assigned names has to be discarded.