Microthyrium ciliatum

Description

The fruit bodies are dark brown to blackish, circular, one cell thick, with central ostioles for spore release. Under the microscope they appear as a series of radiating cells, evenly coloured. They rest on the surface of their host with hyphae holding them in place.

Identification aids

 

Holly Speckle
Trochila ilicina
Phacidium lauri Phomopsis crustosa Microthyrium ciliatum
There are some nice comparison images of species 1, 2 and 4 here.
Small (<1mm) speckles on the upper side of the leaf only. Pustules (c.1.5mm) on upper and lower surfaces of the leaf. Immersed black conidiomata (0.5mm) on brown spots surrounded by a narrow black line. Tiny black speckles (<0.5mm) on both sides of the leaf.
Habitat

Found growing individually and gregariously on both surfaces of dead holly leaves.

When to see it

Whenever dead Holly leaves can be found.

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Leicestershire & Rutland Map

MAP KEY:

Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map