Hydnellum scrobiculatum (Fr.) P. Karst. - Ridged Tooth

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

Hydnellum scrobiculatum - Ridged Tooth

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Thelephorales

Family: Bankeraceae

Although very variable in cap colour, Ridged Tooth fruitbodies invariably have pinkish tones near to the margin and are a darker reddish-brown to mid brown in the centre. Often there are so many fruitbodies in proximity that the caps and even the stems become fused; however, when well spaced they produce rosettes with colourful ridged margins and contrasting centres.

In Britain this 'hydnoid' (toothed) fungus is a Biodiversity Action Plan (BAP) species.

Distribution

The Ridged Tooth is a fairly common but rather localised woodland species in Britain and Europe; it is also found in pine woodland in many parts of North America, where the beautiful specimens shown on this page were photographed by Doug Holland.

Taxonomic history

Tooth fungi of various kinds can be found in many taxonomic orders, and over the years their classification has changed considerably. The basionym of Ridged Tooth was set in 1815 when this species was described scientifically by the great Swedish mycologist Elias Magnus Fries, who gave it the binomial name Hydnum scrobiculatum - effectively implying a close relationship with the Wood Hedgehog and the Terracotta Hedgehog fungi, which also have teeth on their fertile cap surfaces (the undersides). It was not until 1880 that this woodland fungus obtained its currently-accepted scientific name Hydnellum scrobiculatum, when Finnish mycologist Petter Adolf Karsten (1834 - 1917) transferred the Ridged Tooth into the genus Hydnellum, which Karsten himself had circumscribed in the previous year.

Synonyms of Hydnellum scrobiculatum include Hydnum scrobiculatum Fr., and Hydnellum velutinum var. scrobiculatum (Fr.) Maas Geest.

Etymology

Hydnellum, the generic name, is derived from the ancient Greek word hudnon, meaning an edible mushroom; this term was applied particularly to edible truffles. (See, for example, Tuber melanosporum, the Perigord Truffle.)

The specific epithet scrobiculatum means scrobiculate (pitted).

Identification Guide

Cap of Hydnellum scrobiculatum

Description

Cap initially flat topped becoming slightly funnel-shaped with a thin margin; 3 to 6cm in diameter and 1 to 3cm tall; cap flesh thin (<2mm); upper surface concentrically zoned; pink at the margin, darker reddish-brown or rusty cinnamon in the centre; cap flesh tough and fibrous.

The underside of the cap is covered with crowded, purplish-brown spines 1 to 3mm long. Spines are decurrent to the stem

Stems range from 0.5 to 3cm in diameter and are up to 4cm tall, slightly swollen at the base; colour as centre of cap.

 

Spores

Irregularly ellipsoidal to subglobose, 4.5-6.5 x 4-5µm; ornamented with irregular coarse warts; inamyloid.

Spore print

Dull brown.

Odour/taste

No significant odour; taste mild, slightly farinaceous.

Habitat

In mixed woodland, mycorrhizal with pines, growing in the debris of the forest floor; also occasionally found under broadleaf trees.

Season

August and September in Britain.

Similar species

Hydnellum concrescens is very similar but is found under oak and Sweet Chestnut trees; it has slightly larger spores.

The flesh of Hydnellum peckii tastes very hot indeed; its young caps frequently exude red droplets, giving it a 'strawberries and cream' appearance.

Hydnum rufescens is tan coloured withiout concentric zones; its spines are adnate to the stem rather than decurrent.

Culinary Notes

In common with the other members of the genus Hydnellum, Ridged Tooth is a tough and insubstantial fungus. The fact that the fruitbodies are long-lasting fungus suggests that other creatures also find the Zoned Tooth hard to chew and swallow (although it is possible that these fungi contain chemicals that grazing animals do not like). Needless to say we have no recipe information for this species.

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.