Volvariella surrecta (Knapp) Singer - Piggyback Rosegill

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Agaricales - Family: Pluteaceae

Volvariella surrecta growing on a Clouded Funnel Clitocybe nebularis

Amanita fungi are not the only ones that have a volva at their stem base; mushrooms in the genus Volvariella do so as well. Volvariella surrecta is one of the rare members of this genus, and it has very particular habitat requirements. The Piggyback Rosegill grows on old and decaying fruitbodies of the Clouded Funnel, Clitocybe nebularis. (Very occasionally it hitches a ride of other kinds of mushrooms, but as it is a rare species the chances of seeing it anywhere but on a Clouded Funnel are extremely remote.)

Clitocybe nebularis - most are not parasitised by Volvariella surrecta

Unfortunately the vast majority of Clouded Funnels (as shown above) decay without attracting the attention of the Piggyback Rosegill.

Distribution

The Piggyback Rosegill is a rare sight in Britain and Ireland, where it is most often reported from southern England. Volvariella surrecta has been recorded in many other European countries as well as in North Africa, parts of North America, and New Zealand.

Taxonomic history

When English botanist John Leonard Knapp (1767 - 1845) described this remarkable mushroom in his 1829 Journal of a Naturalist, he referred to it as Agaricus surrectus and stated that it grew from the back of another mushroom which he called Agaricus casaeus - almost certainly the Clouded Funnel Clitocybe nebularis.

It was German-born American mycologist Rolf Singer who, in 1949, redescribed this mushroom, transferring it to the genus Volvariella so that its scientific name became Volvariella surrecta. (Some of the former Volvariella species may have been relocated to a new genus Volvopluteus by the time you read this!)

Synonyms of Volvariella surrecta (Knapp) Singer include Agaricus surrectus Knapp, Agaricus loveianus Berk., Volvaria loveiana (Berk.) Gillet, and Volvaria surrecta (Knapp) Ramsb.

Etymology

Volvariella, the genus name, is a reference to the volva formed around the stem base by the remnants of the membranous universal veil which covers embrionic fruitbodies. The specific epithet surrecta comes from the Latin surrectus meaning arisen (just as resurection means rising again).

Identification guide

Cap, stem and volva of Volvariella surrecta, the Piggyback Rosegill

Cap

3.5 to 8cm across; initially oval becoming convex but not often flattening completely; white, often with a greyish-brown centre, becoming cream and eventually turning ochre from the centre; its surface is silky or finely hairy.

Stem and volva

3 to 6cm long and 0.5 to 1.2cm diameter.; white; tapering towards apex; no ring. There is a persistent fleshy sack-like volva at the base.

Gills of Volvariella surrecta

Gills

Gills of Volvariella surrecta are free, broad andcrowded. White at first, they gradually turn pink as the spores mature.

 

Spores

Ellipsoidal, smooth, 5-7 x 3-5µm.

Spore print

Pink.

Odour/taste

Pleasant and mild but not distinctive.

Habitat & Ecological role

Parasitic and/or possibly saprobic on decaying Clouded Funnels Clitocybe nebularis and occasionally on other white-spored mushrooms, notably Tricholoma species.

Season

July to November in Britain and Ireland.

Similar species

Volvariella bombycina has a very silky (almost hairy) cap and a volva; it grows on damaged hardwood trees and on their dead trunks and large branches.

Amanita virosa has a stem ring and occurs in woodland habitats.

Culinary Notes

The Piggyback Rosegill is rare and should not be gathered for eating. Volvariella species can easily be confused with deadly Amanita species (such as Deathcap and Destroying Angel) which also have stem-base volvas and pale caps, and therefore inexperienced mushroom gatherers should avoid gathering any fungus that has a volva.

Reference Sources

Fascinated by Fungi, Pat O'Reilly 2016.

Alfredo Justo, Andrew M. Minnis, Stefano Ghignone, Nelson Menolli Jr., Marina Capelari, Olivia Rodríguez, Ekaterina Malysheva, Marco Contu, Alfredo Vizzini (2011). 'Species recognition in Pluteus and Volvopluteus (Pluteaceae, Agaricales): morphology, geography and phylogeny'. Mycological Progress 10 (4): 453–479.

Orton, P.D. (1986). British Fungus Flora: Agarics and Boleti. Vol 4. Pluteaceae: Pluteus & Volvariella. Royal Botanic Garden: Edinburgh, Scotland.

BMS List of English Names for Fungi

Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers; CABI, 2008

Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi and (for basidiomycetes) on Kew's Checklist of the British & Irish Basidiomycota.

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