Grassland Fungi

Waxcaps have been described as the orchids of the world of fungi. They are often startling in colour from reds, oranges and yellows to whites and browns. They can smell of honey or less pleasantly rather nitrous. They are usually found in grasslands here in Ireland (although also in woods) and are one of the groups of grassland fungi that are now recognised as excellent indicators of ancient unfertilised grassland. Other grassland types are the Entolomas (pink spored gill fungi), the Clavarioids (coral fungi) and Geoglossums or Earth tongues. They can all be found in a range of grassland types from dunes to uplands, from lowlands to gardens. Indeed some of the best species like Hygrocybe calyptriformis (see photo below) are more often found in gardens than other grassland types. Hygrocybe calyptriformis is actually a Biodiversity Action Plan species so if you find this species in particular in your garden, please e-mail us – we want to know wherever you live whether it be Northern Ireland or not.

These species are sensitive to the application of artificial fertilisers, especially those containing phosphorus. It may take a considerable time for fertilised sites to be rehabilitated even if managed positively for nature conservation arguably making grassland fungi better indicators of ancient unfertilised grasslands than higher plants.

The great unknown however is just what these species are actually doing in the soil. They seem linked with mosses, but, if that is right, how? A recent paper (Griffith, G.W., Easton, G.L. & Jones, A.W. (2002). Ecology and Diversity of Waxcap (Hygrocybe spp.) Fungi. Bot.J.Scotl. 54(1), 7-22) points to some possible answers based on stable isotope analysis. Stable isotopes of Carbon (13C) and Nitrogen (13C) occur naturally and work looking at the patterns of 13C and 13C enrichment in ectomycorrhizal and saprophytic fungi have shown quite different enrichment patterns. When Waxcaps have been looked at, preliminary work by Griffith et al, has shown them to have very different patterns from both ectomycorrhizal and saprophytic fungi. They are more depleted in 13C and more enriched in 13N. Clavarioids and Geoglossaceae are even more different, but Entolomas are more typical of saprophytic fungi. This could mean that Hygrocybe spp., Clavarioids and Geoglossaceae could be deep humic decayers rather than normal surface litter decayers. The fact that Entolomas are more typical saprophytes supports the idea that sites good for Waxcaps are not necessarily good for Entolomas.

Assessing site quality from fungal data

The British Mycological Society instigated a Waxcap survey in 1996 and this instigated a lot of interest in surveying waxcap sites. Sites can be ranked based on the number of species of Hygrocybe or additionally using a weighted scoring system, sites with few visits but good species can be highlighted for further survey. See also the paper  “The Fungi of Irish Grasslands and their value for nature conservation” by Roland McHugh, David Mitchel, Mark Wright and Roy Anderson in Biology and Environment, Vol 101B, No.3, 225-242 (2001).

The article in Biology and Environment lists the sites known in Ireland at that time. The more detailed page about Waxcaps in Ireland and Wales here will offer the most up to date site rankings of Irish and Welsh grassland fungi.

See the Atlas for more details on the distribution of these species in Northern Ireland or the Photo Gallery for images of these species.

More interesting web links about Waxcaps

Taxonomy changes to the genus Hygrocybe

Recent DNA work has transformed the genus Hygrocybe and it can be difficult to remember names now! This is a diagram of how the genus has been split and what species have gone where.