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BIODIVERSITY REFERENCE
 
   Hygrocybe spadicea (Scop.) P.Karst.   
 
'Date Waxcap'


Kingdom: Fungi
Phylum: Basidiomycota
Order: Agaricales

British distribution: Widespread but rare.    (British Red Data List and UKBAP species, "Vulnerable")
World distribution: Europe, North America, New Zealand.


Hygrocybe spadicea, studio shot
Hygrocybe spadicea, Ayrshire, Scotland, 1995.


Ecology
Although there are scattered records throughout Britain, Hygrocybe spadicea is one of our rarer waxcap fungi and one that is currently the subject of a national Biodiversity Action Plan. It seems to require soils of high base status and is generally said to be a species of limestone and calcareous dune turf, but Bon (1987, 1990) notes its occurrence also on basalt. Here in south-west Scotland, the recent occurrences of H. spadicea have been on basalt (Renfrewshire) and on another ultrabasic rock, serpentinite, in south Ayrshire. Boertmann (2010) describes the typical habitat in Denmark as "unfertilized grasslands, often in the driest parts like hillsides facing south, or in sites with exposed limestone". The Renfrewshire and Ayrshire sites match this description in being ancient pasture on south (Ayrshire) or south-east (Renfrewshire) facing slopes, where only thin soil covers outcropping rock. H. spadicea is, therefore, a rare and apparently demanding component of waxcap grasslands, ancient, 'unimproved' pastures that have not been reseeded or subjected to chemical fertilisers.


Identification and variation
Hygrocybe spadicea is a non-blackening species with a distinctly conical cap. Within this group, it is distinctive with its cap being mahogany to blackish-brown and strongly fibrillose, contrasting with the persistently bright yellow gills and flesh. The cap is viscid at first but dries with age.

Confusion could come with some members of the H. conica complex, in which colours are sometimes dull and may go through a brownish phase, and in which the gills are initially yellow. However, these are blackening species, fruitbodies eventually becoming completely black, and the gills usually begin to turn grey relatively quickly.

Confusion may also be possible with H. psittacina var. perplexa (= H. sciophana) an uncommon, upland variety of the Parrot Waxcap, lacking the usual green colours and having a brick-red to brown, often somewhat conical cap and orange gills. However both cap and stem are persistently very viscid (covered in 'slime') in this taxon, and the cap cuticle does not split into fibrils.

Although the bright yellow flesh and gills are a distinctive feature of H. spadicea, a variant, var. albifolius, with gills and flesh white, and remaining so, occurs in North America (detailed description in Hesler and Smith, 1963). It has been reported from Denmark and there are now records from calcareous sites in North Scotland (FRDBI).

There is also a Hygrocybe citrinofusca, described as a new species (as Hygrophorus citrinofuscus) by Favre (1960) from the Swiss Alps. Both Bon (1990) and Boertmann (2010) suggest it might have been H. spadicea but Favre's colour plate, at least in my own reprint copy, shows a fungus with dull yellowish colours, evidently flushed brownish on the cap, which is umbilicate, not conical. It might be worth looking for in montane turf in the UK.


From M.C.Cooke (1881-91), Illustrations of the British Fungi (Hymenomycetes), plate 1194(1161).
("Hydrocybe" was a printing error, as were the imperfections in the background of the plate)


References
•   Boertmann, D. (2010). The genus Hygrocybe, 2nd revised edition. Fungi of Northern Europe vol. 1, Danish Mycological Society.
•   Bon, M. (1987). The mushrooms and toadstools of Britain and North-western Europe, Hodder & Stoughton, London.
•   Bon, M. (1990). Flore mycologique d'Europe. 1. Les hygrophores. Documents Mycologiques Mémoire hors série 1, Hygrophoraceae Lotsy, L'Association d'Ecologie et de Mycologie, Lille.
•   Favre, J. (1960). Catalogue descriptif des champignons supérieurs de la zone subalpine du Parc National Suisse. Résultats des Recherches scientifiques entreprises au Parc National Suisse, new ser., 6 (42).
•   Hesler, L.R., & Smith, A.H. (1963). North American species of Hygrophorus, University of Tennessee Press, Kingsport.


Biodiversity Action Plan link (archived)
http://tna.europarchive.org/20110303145238/http://www.ukbap.org.uk/UKPlans.aspx?ID=383
(last verified 29.05.2014)



© A.J. Silverside
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