Xerula radicata (Relhan: Fr.) Dörfelt - Rooting Shank

Distribution - Taxonomic History - Etymology - Identification - Culinary Notes - Reference Sources

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Agaricales

One of the early-fruiting wood rotters, Xerula radicata is a tall and very graceful mushroom. The stem has 'hidden depths': this woodland beauty usually has as much of its stem below the forest floor as above.

Distribution

Rooting Shank is a fairly common woodland mushroom throughout Britain and Ireland; it occurs also in most parts of mainland Europe and in North America.

The majority of wood-rotting fungi show a marked preference for either hardwoods or softwoods, but I have found Rooting Shanks under conifers and, almost as frequently, under broadleaf trees.

Taxonomic history

When British botanist/mycologist Richard Relhan (1754 - 1823) described this mushroom in 1785 he named it Agaricus radicatus. (Most of the gilled fungi were initially placed in a giant Agaricus genus, now redistributed to many other genera.) Being something of an oddball in terms of appearance and growing habit, it is perhaps unsurprising that there has been much debate about where this species sits in the taxonomic system. Rooting Shank has therefore acquired many other scientific names over the past 230 years. Its current scientific name Xerula radicata dates from a 1995 publication by the German mycologist Heinrich Dörfelt (born 1940).

Synonyms of Xerula radicata include Agaricus radicatus Relhan, Gymnopus radicatus (Relhan) Gray, Collybia radicans P. Kumm., Collybia radicata (Relhan) Quél., Mucidula radicata (Relhan) Boursier, Oudemansiella radicata (Relhan) Singer, Xerula radicata var. alba Dörfelt, Oudemansiella radicata var. marginata (Konrad & Maubl.) Bon & Dennis Oudemansiella radicata (Relhan ex Fr.) Singer, and Collybia radicata (Relhan ex Fr.) Quél.

Xerula is a very small genus with just four species recorded in Britain, and of these Xerula radicata is by far the most common.

Etymology

The specific epithet radicata means rooting.

Identification guide

	Cap Pale grey-brown to mid brown (the beautiful specimen on the left is a deeper brown than is typical, but the cap colour in this species is very variable); 4 to 10cm across; convex or bell-shaped, becoming flatter and umbonate; sticky when moist, drying silky with radial wrinkles.
	Gills Adnate with a decurrent tooth; distant; pale cream with browner edges. Stem 10 to 20cm long and 0.5 to 1cm dia., base rooting in buried wood; finely grooved; white at apex, browner near base; no ring.
	Spores Subglobose to broadly ellipsoidal, 12-17 x 9-14μm. Spore print Pale cream.
Odour/taste	Not significant.
Habitat	Saprobic, rooting on rotten wood, often buried deep beneath leaf litter.
Season	Summer and autumn.
Similar species	Could possibly be confused with mushrooms of the Pluteus genus, but a spore print (spores are pink in mass for Pluteus) would resolve any doubt.

Culinary Notes

Rooting Shank is generally regarded as an edible mushroom, but it is not highly rated and, because it rarely occurs in any great numbers, not worthwhile.

Reference Sources

Fascinated by Fungi, Pat O'Reilly 2011

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.

Heinrich Dörfelt (1979 - 1986) 'Taxonomische Studien in der Gattung Xerula' (Taxonomic Studies in the Genus Xerula) in Feddes Repertorium.