Sycamore Tarspot - Rhytisma acerinum

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Alternative names
Tarspot Fungus
Description

This forms large black tar-like spots on living Sycamore leaves.  In summer, apothecia contaning immature spores can be seen on the surface.  The spores mature over winter in fallen leaves, and in Spring the stroma cracks open and the spores are released in time to infect new leaves. .  

Identification difficulty
Recording advice

Photograph on leaf, note substrate and associated tree species

Habitat

Mainly Sycamore, occasionally Norway Maple, rarely Field Maple 

When to see it

Late Summer until the leaves fall in Autumn.

VC55 Status

Very common

  • Alan Semper
    Harby churchyard
    16 November 2011
  • Melinda Bell
    Ashby,Footpath alongside A42
    28 August 2022
  • David Nicholls
    Kirby Muxloe Castle
    25 August 2012
  • Graham Calow
    Sapcote, Hinckley Road
    03 August 2020
    on Sycamore
  • Hannah Keys
    Wistow canal, leicestershire
    05 October 2024
  • Mark Skevington
    Whetstone
    16 September 2024
  • Saharima Roenisch
    Field adjacent to Stoughton Lane
    02 December 2017
  • Hazel Graves
    Rocky Plantation
    27 October 2023
  • Ray Pearce
    Whitehorse wood, Shepshed
    07 March 2018

Leicestershire & Rutland Map

MAP KEY:

Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2025+ | 2020-2024 | pre-2020

UK Map

Species data profile ?

Species profile

Common names
Tar-Spot Fungus, Sycamore Tarspot
Species group:
fungus
Kingdom:
Fungi
Order:
Rhytismatales
Family:
Rhytismataceae
Records on NatureSpot:
307
First record:
26/10/2008 (Calow, Graham)
Last record:
19/11/2025 (Pugh, Dylan)

Total records by month

% of records within its species group

10km squares with records

The latest images and records displayed below include those awaiting verification checks so we cannot guarantee that every identification is correct. Once accepted, the record displays a green tick.

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Latest images

Latest records

  • Graham Calow
    Sapcote
    26 October 2008
    On Sycamore
  • David Nicholls
    Change Spinney, Ratby
    17 November 2011
  • David Nicholls
    Croft Hill
    29 September 2011
  • David Nicholls
    Abbey Park
    19 September 2010