Hymenopellis radicata (Relhan) R.H. Petersen - Rooting Shank

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

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

One of the early-fruiting wood rotters, Hymenopellis radicata (until recently much better known as Xerula radicata, and before that as Oudemansiella 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 thr/ughout 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. Occasionally, as in the picture below, these attractive fungi can cause confusion by appearing on low-down deadwood parts of living trees that have suffered damage to their basal roots.

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, most of whose contents have since been 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 recent scientific name Xerula radicata dates from a 1995 publication by the German mycologist Heinrich Dörfelt (born 1940); however, in 2010 American mycologist Ron Petersen (b. 1934) circumscribed the new genus Hymenopellis with Hymenopellis radicata as the type species.

Synonyms of Hymenopellis 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. and Xerula radicata (Relhan: Fr.) Dörfelt.

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 slight decurrent tooth; distant; pale cream, with browner edges when fully mature.
	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 Broadly ellipsoidal to lemon-shaped, smooth, 12-17 x 9-14μm, with a germ pore; inamyloid. Show larger image Spores of Hymenopellis radicata, Rooting Shank  X  Spore print White.
	Basidia 4-spored. Show larger image Basidia of Hymenopellis radicata, Rooting Shank  X
	Chaelocystidia Broadly clavate. Show larger image Cheilocystidia of Hymenopellis radicata, Rooting Shank  X
Odour/taste	Not significant.
Habitat & Ecological role	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, 2nd Edition, Pat O'Reilly 2016, reprinted by Coch-y-bonddu Books in 2022.

Petersen R. H, Hughes K. W. (2010). The Xerula/Oudemansiella complex (Agaricales). Beihefte zur Nova Hedwigia. 137. Gebruder Borntraeger Verlag. p. 80

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.

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

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