Mossy Willow Catkin Gall


This gall is actually an abnormally distorted catkin, and is probably caused by a virus or phytoplasma ( a type of Bacteria), but the precise causer has not yet been identified. It used to be thought that it was caused by the mite Stenacis triradiatus but it now seems that the mites just choose to live in and around these galls. The galls can be very large and variable in shape and degree of distortion of the catkin - often the gall forms a green straggly mass, or it can be more of a woody mass.

They may persist on the willows into winter.

Identification difficulty



On various willows.

When to see it

Summer growths persist into winter when they can be particularly prominent.

UK Status

Status in Britain not known.

VC55 Status

Status in Leicestershire and Rutland not known.

Leicestershire & Rutland Map


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

UK Map

This species or aggregate is not available on the NBN Atlas currently

Species profile

Species group:
Algae, Bacteria, Virus
Records on NatureSpot:
First record:
01/08/2011 (Semper, Alan)
Last record:
26/08/2023 (Willis, Jill)

Total records by month

% of records within its species group

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