“Great fleas have little fleas upon their backs to bite ’em, And little fleas have lesser fleas, and so ad infinitum.” – Augustus De Morgan, based on a verse by Jonathan Swift.

Piggyback Rosegill, Volvariella surrecta

Previously I have written about parasitic plants such as Mistletoe, Ivy Broomrape and Purple Broomrape. Piggyback Rosegill, Volvariella surrecta, is a parasitic fungus, which grows on the caps of another fungus. In the photograph above, the smaller, button-like fungus is the Piggyback Rosegill and it is feeding on the decaying bigger fungus underneath it.

Piggyback Rosegill’s host is the Clouded Funnel, Clitocybe nebularis, a very common fungus that can be found in both broadleaved and coniferous woodland and at the bottom of hedgerows. It is saphrotrophic, obtaining the nutrients it needs from decaying organic matter. Clouded Funnels have a slightly funnel shape when mature and are usually grey, sometimes with a cloud-like pattern in the centre, hence the English name. They often grow in large fairy rings.

Clouded Funnels, Clitocybe nebularis.

Piggyback Rosegill can apparently grow on other species of fungus as well (species of Tricholoma, the Knights), but this is very rare.

On the Scottish Fungi website, Liz Holden discusses whether the Piggyback Rosegill is an obligate parasite (i.e. is it reliant on living Clouded Funnels?) or a host specific saprotroph (i.e. does it just feed on rotting Clouded Funnels?). She concludes that the truth “might be a bit of both“.

The Scottish Fungi website uses an alternative English name, Piggyback Pinkgill. Volvariella surrecta has free, broad and crowded gills, which are white in younger specimens before turning pink as the spores mature, to give the fungus its English names. The First Nature website has further information to help with identification, and some good detailed photographs.

Some fungi don’t produce their fruitbodies every year but in my experience Clouded Funnel is a reliable performer, putting in an appearance every autumn in the places where I’ve found it.

In contrast, Piggyback Rosegill is described as “uncommon to rare” (Sterry and Hughes 2009) and “tends to turn up with any regularity only in a few places” (Marren 2012). The First Nature website says it is a rare sight in Britain and Ireland, mostly found in southern England. The Carmarthenshire Fungi website describes a sighting from Wales and the species has been seen from at least one site in Scotland. Further afield it has been recorded from many other European countries, North Africa, parts of North America, and New Zealand. In the Norwich area it had only been sighted at Colney Woodland Burial Ground and on Mousehold Heath, but within the last week we have found it in Earlham Cemetery on a fungus walk and in Train Wood. 2017 seems to be a good year for finding it.

Clouded Funnels can be found from August to early December and Piggyback Rosegills are normally found in October and November.

Piggyback Rosegill in Train Wood, Norwich

Thanks to James Emerson for identifying the latest Piggyback Rosegills in Norwich.