#24 Taphrina carpini by John Newbould
Meet John Newbould, Volunteer Specialist for the Natural Trust!
John has notionally retired. He has been involved with wildlife surveying for over 45 years and has contributed many records and reports to NEYEDC and Rotherham BRC. He was President of the Yorkshire Naturalist’s Union in 2013, previously Secretary and Treasurer for too many years. Currently he lives in Dorset, where he is a Volunteer Specialist for the National Trust (Nature Evidence Team) based with the West Dorset Team. As a National Trust Volunteer Specialist, he led on completing Nature Conservation Assessments with YNU members of Hudswell Woods, Richmond (2013—14) and Beninborough Hall Gardens (2015). He also organised a number of week-long surveys based in Reeth surveying Swaledale and Arkengarth Dale 2009-2015. On principle he does not have a Linkedin profile and has never heard of Facebook… but he does use iRecord extensively!
During John’s years as a YNU Trustee, he spent many weekends staying in Harrogate with Sunday an opportunity for surveying. The results of these are reflected in his chosen species, an Ascomycete fungus from Taphrinaceae, the plant gall Taphrina carpini on Hornbeam (Carpinus betulus). A gall is an abnormal growth produced by a plant or other host under the influence of another organism, in this case, a fungus. This involves the enlargement and sometimes proliferation of the plant host, which provides both shelter and food or nutrients for the invading organism. Taphrina carpini forms conspicuous ‘witches’ brooms’, a kind of structural change or deformity, on Hornbeam trees. Typically, they result in bunches of stem, root, or leaf material growing from one point in the tree. The tangles of densely branched small twigs are said to resemble a witches’ broom, giving the gall its name. These galls do not always negatively impact their host, but this can occur. Taphrina carpini is a fungus that spread spores, dependent on wind for dispersal rather than water, like other Ascomycete spores.More about T. carpini can be found on the NBN atlas. As a group that is present throughout and beyond autumn, John began recording galls some years ago in efforts to keep recording when other plants were no longer present - so keep your eyes peeled this autumn!
Taphrina carpini on hornbeam (Carpinus betulus), RHS Harlow Carr Garden, Harrogate, 2010. The proliferation of the leaves and other plant material to create the witches’ broom can be seen clearly here.
There are just 48 records of this gall fungus on the NBN Atlas, many from Essex and Sussex, and just one from West Yorkshire, via the British Mycological Society in SE2812, Bretton Park. Over the years however, John has provided NEYEDC with five records from 2010 and 2011 in the Harrogate district. A study in 2002 mapped Hornbeam as a native tree in 1,250 10km squares in Britain, with a mainly southern and eastern distribution. Indeed, most consider its natural distribution to be in the south of England. In mid-west Yorkshire, it is considered an introduced species, widespread and infrequent, in woodland. John suspects that the Hornbeam at Harlow Carr was introduced to the garden in the days of the Northern Horticultural Society, bringing the fungus where from there the wind carried spores to other trees within the Harrogate district, explaining its unexpected appearance in the north. John has recorded Hornbeam within the Harrogate area in Hollybank Wood, Ripley Park, and as a hedgerow bush at Clint. Between 2002 and 2009, the gall was not present in any of these locations, but thanks to John’s records, we know it was present in the Harrogate area in 2010 and 2011.
A young gall on a tree in Ripley Park.
During May 2022, John re-visited Harlow Carr for the first time for many years, when he was mightily impressed with the alterations. He is also pleased to report that the hornbeam is still there with 20 witches’ brooms, despite a wall being knocked down adjacent. He is also pleased to note that the RHS have put a notice explaining the significance of the witches’ brooms but thinks this article offers a better explanation.
Whilst Taphrina carpini forms unusual witches’ brooms as its gall, there are 24 recognised species of Taphrina galls (see keys in Redfern and Shirley) with a range of resulting galls on the host plant. T. deformans, for example, causes ‘peach leaf-curl’ on peach trees, causing thickened and distorted leaves that range from green to a bright red in colour. T. padi is a gall known as a pocket plum, which occurs on bird cherry. T. padi chemically induces distortion of the fruits which become swollen, hollow, and elongated – this is the reason for T. padi’s other name as a ‘tongue fungus’. In the early 2000s, nearly every blackthorn fruit nationally was deformed and useless with T. pruni, another fungus which causes similar effects on fruiting bodies to T. padi. Perhaps more obscure to some of us, it is amazing to consider the breadth and complexity of the galls that we may previously have missed or overlooked – and a good reason to take a closer look in our woodlands and parks!
Monitoring
Taphrina betulina witches’ brooms on silver birch – showing how frequent galls can be on a single plant.
Plant Galls are monitored in Yorkshire by members of the Yorkshire Naturalists’ Union (Recorder Mr Tom Higginbottom) and the British Plant Gall Society of which at the time of writing Tom is the Secretary.
Acknowledgements and further information
NEYEDC would like to thank John for his time and expertise in helping to create this blog. For more about plant galls, see the field guide British Plant Galls by Redfern and Shirley, published through the Field Studies Council.