Hygrocybe chlorophana (Fr.) Wünsche |
British distribution: Throughout Britain.
World distribution: Europe, Asia, North America.
|Hygrocybe chlorophana in hill pasture near Loch Thom, Renfrewshire, October 2001.|
Hygrocybe chlorophana is one of our most common waxcap fungi and a characteristic species of waxcap grasslands. Like most waxcaps it is a species of ancient, 'unimproved' pastures that have not been reseeded or subjected to chemical fertilisers, though it is less ecologically restricted than many and can also be seen in established lawns (maybe 20 years or more old, as judged by its occurrence on the University campus).
Identification and variation
While, like most waxcaps, it is best confirmed on microscopical characters, it can usually be told in the field by its relatively large size, up to 7 cm diameter, its usually uniformly yellow colour, viscid or moist cap, stem viscid only when young, and its distinctly pale gills which are ascending and only narrowly attached to the stem (adnexed). It is included in many popular guides to the larger fungi and is well depicted and described by Boertmann (1996). Occasionally it can be deeper orange, in whole or in part (var. aurantiaca Bon), but microscopical confirmation is essential.
It should be noted that, as with many waxcaps, published photographs or those posted on the Internet may not always be reliably named. There is much confusion among the yellow species.
There is a tradition of recognising a separate species with the stem more or less dry from the start (and a correspondingly thinner stem cuticle when examined in cross-section under the microscope) and such fruit bodies have been said to be more orange when young. This taxon has been known as H. flavescens (or H. euroflavescens if the former is considered to be restricted to North America).
Boertmann (op. cit.) considers that the two "species", H. flavescens in the European sense and H. chlorophana, completely intergrade, and that this is simply a range of variation within the one species, H. chlorophana. In my own experience of British "H. flavescens", I have found it impossible to distinguish reliably, either macroscopically or microscopically, from more typical H. chlorophana, and I emphatically agree with Boertmann's treatment.
Other common, yellow species with rounded, not conical, caps are:
|• ||H. glutinipes, reliably separated by the structure of the stem tissues but recognisable macroscopically by its smaller size, neater appearance and, importantly, its persistently viscid stem;|
|• ||H. ceracea, which has shortly decurrent gills that are pale at first but are soon a rich chrome yellow;|
|• ||H. quieta, sometimes plain yellow but more deeply coloured than H. chlorophana, and more often dull orange, with orange gills and a strong oily, 'bedbugs' smell;|
|• ||H. psittacina is persistently viscid and, even when entire populations have plain yellow caps, there is usually some green colour at the stem apex.|
Boertmann, D. (2010). The genus Hygrocybe, 2nd revised edition. Fungi of Northern Europe vol. 1, Danish Mycological Society.