Trichoglossum walteri – a fungus
Trichoglossum walteri (Berk.) E.J. Durand
Family: Geoglossaceae
Earth tongues are one of the groups of fungi that are indicators of old unfertilised grassland. They are not possible to identify without microscopic examination, but this species is fairly distinctive under the microscope.
In brief
- There are five records of this species in Northern Ireland
- Found in old semi-natural grasslands in habitats ranging from upland acidic grassland to neutral grassland with one of the latter habitats being a churchyard
- Fruiting bodies have been recorded from September to November in Northern Ireland
- This is a rare fungus and its presence indicates that the site is likely to be rich in other fungi of conservation concern
- The main threats are due to agricultural intensification (especially the application of fertilisers), habitat neglect, reduction of habitat and lack of awareness.
Species description
It is like a black finger sticking out of the ground and can be up to 9cm high. It sometimes has a flattened head with a distinct groove running vertically down the fruiting body. Its stem can be brownish and appears hairy with jet black needle like structures (setae) projecting from the fruiting body which can be seen with a hand lens. As it is an ascomycete (spore shooter), it forms spores on the outside of the fruiting body. These have to be examined microscopically to be able to identify the species. When this is done, the setae are very distinctive. The spores also have to be examined. The spores are narrow, 70-100µm long and are consistently seven septate (perpendicular divisions within the spores) when mature.
Life cycle
The earliest fruiting body recorded in Northern Ireland was found on 30 September and the latest on 7 November. Earth tongues typically appear late in the season with a peak in November and are often found in December as well so it would not be surprising if this species is also found so late in the season.
Similar species
It is almost impossible to tell earth tongues apart without looking under the microscope. However, if you look carefully, the jet black setae of this species projecting from the fruiting body can usually be seen with a hand lens and this identifies it as a Trichoglossum. The most common Trichoglossum is T. hirsutum, but this is distinguished by longer spores that are up to 15 septate. If spores are consistently 7 septate (as in T. walteri), make sure they are not longer broken spores of T. hirsutum. Trichoglossum spores should have obtuse, rounded ends and not perpendicular edges. Two other rare species of Trichoglossum that have not yet been recorded in Northern Ireland must also be checked for by examining the spores. T.rasum has 7 to 9 septate spores that are longer than those of T. walteri and T. variable has spores that are 9 to 12 septate.
How to see this species
This species has scattered records across Northern Ireland from Hillsborough Parish Church lawn to Monawilkin ASSI in Fermanagh to Slemish and near Torr Head in Antrim and Edenderry near Belfast. Earth tongues are not easy to see. They need to be searched for unless they are abundantly fruiting and then they can almost form carpets across a grassland. However, there are often a number of species growing together and this is often not apparent until the specimens are examined under the microscope.
Current status
This is a widespread but rare species across Northern Ireland and the British Isles although records are more concentrated in the north and west.
Why is this species a priority in Northern Ireland?
- It is a rare and declining species with Northern Ireland being the Irish stronghold.
It is an excellent indicator of old unfertilised grasslands. This habitat is known to be decreasing in extent from the Northern Ireland Countryside Survey.
Threats/Causes of decline
The main reasons for decline are agricultural intensification (primarily the application of phosphorus and other nutrients) and habitat loss. Grassland neglect where the sward becomes rank also restricts fruiting although it is not clear if this affects the organism under the ground.
Conservation of this species
Current action
- One of the five sites is covered by an ASSIdesignation
- A grassland fungi survey funded by EHS for the whole of Northern Ireland 2002-04 produced a good overview of the distribution of the species
- Production of Grassland Fungi conservation leaflet by Fungal Conservation Forum
- Implementation of the Northern Ireland Habitat Action Plans for Lowland Meadow, Lowland Dry Acid Grassland and Calcareous Grassland.
Proposed objectives/actions
- Publicise conservation value and management requirements of this species amongst managers of existing / potential sites
- Research into ecological requirements.
What you can do
Some species of fungi can be difficult to identify, but if you are interested, please contact the Northern Ireland Fungus Group for details of how to record fungi. Records can be sent in using online recording forms or by contacting david.mitchel@nifg.org.uk.
Further information
Links
Northern Ireland Fungus Group
Northern Ireland Habitat Action Plans
Literature
Hansen, L. and Knudsen, H. (2000). Nordic Macromycetes Vol. 3 Nordsvamp, Copenhagen.
McHugh, R., Mitchel, D., Wright, M. and Anderson, R. (2001). The fungi of Irish grasslands and their value for nature conservation. Proceedings of the Royal Irish Academy 101B (3), pp. 225-242. download as pdf from RIA website 650kb. .
Newton, A.C., Davy, L.M., Holden, E., Silverside, A., Watling, R. and Ward, S.D. (2002). Status, distribution and definition of mycologically important grasslands in Scotland. Biological Conservation, 111, 11-23
Text written by:
David Mitchel
iNaturalist: Species account : iNaturalist World Species Observations database