Hydnellum concrescens (Pers.) Banker - Zoned Tooth

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Thelephorales - Family: Bankeraceae

Hydnellum concrescens, Zoned Tooth, closeup

The Devil's Tooth is a rare woodland mushroom; it blends in with (and often engulfs), pine needles on the forest floor and so can easy be overlooked. Although very variable in cap shape and colour, the fruitbodies invariably have pinkish tones. Young caps are often (but not always) decorated with bright red liquid droplets that exude from the upper surface. Particularly beautiful when solitary, the fruitbodies more often occur in small groups that merge and become fused at the caps and sometimes also at the stems.

Hydnellum concrescens, Zoned Tooth, group

Distribution

Rarely if ever found in Britain except in Scotland and then most often in the Caledonian Forest, where in some years it is abundant, Zoned Tooth is still fairly localised. All official records for this species on the Fungal Records Database of Britain and Ireland (FRDBI) are from Scotland.

Zoned Tooth, underside view

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 Zoned Tooth was set in 1796 when this species was described scientifically by Christiaan Hendrik Persoon, who gave it the binomial name Hydnum concrescens. The currently-accepted scientific name of this fungus dates from 1906, when American mycologist Howard James Banker (1866 - 1940) transferred this species to the genus Hydnellum.

Synonyms of Hydnellum concrescens include Hydnum concentricum (Fr.) P. Karst., Hydnum zonatum Batsch, Hydnum concrescens Pers., Hydnum queletii Fr., Hydnellum zonatum (Batsch) P. Karst., and Hydnellum velutinum var. zonatum (Batsch) Maas Geest.

Zone Tooth, a large group

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 concrescens means congealed - a reference to the habit of Zoned Tooth fruitbodies of merging and fusing together to form large compound ground-hugging fruitbodies.

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

Identification Guide

Cap surface of Hydnellum concrescens

Cap

Individual caps range from 2 to 5cm across when fully developed, sometimes round but often oval or multi-lobed; initially shallowly domed or flat topped but with a finely velvety bumpy surface, becoming slightly funnel-shaped; white or very pale pinkish-buff, palest near the margin, becoming buff all over and eventually turning brown from the centre before blackening and decaying. The cap flesh is tough and fibrous.

Total above-ground height of a fruitbody ranges from 3 to 9cm.

Caps and stems of fused Hydnellum concrescens

Spines

1 to 5mm long (shortest near to the cap margin) and less than 1mm in diameter; crowded, decurrent; pinkish, becoming buff and later as the spores mature.

Stem

The stem of the Zoned Tooth fungus is very variable in size, sometimes as squat as just 1cm in height; occasionally as tall as 3 or 4cm but with much of the stem below ground; diameter typically ranges from 0.7 to 2cm; usually tapering downwards from the cap before becoming bulbous at the base. Pinkish buff like the outer region of a mature cap, the stem is velvety in texture.

Spore of Hydnellum concrescens

Spores

Irregularly subspherical, 5.5-6 x 4-4.5µm; ornamented with coarse warts; inamyloid.

Show larger image

Spore print

Dull brown.

Odour/taste

Odour slightly farinaceous; taste bitter.

Habitat & Ecological role

Mycorrhizal, on soil in mixed woodland; nearly always with oaks present but also associated with Sweet Chestnut.

Season

Late summer and autumn in Britain.

Similar species

Hydnellum scrobiculatum is very similar but is found under pine trees; it has slightly smaller spores.

Hydnum rufescens is tan coloured without concentric zones; its spines are adnate to the stem rather than decurrent.

Culinary Notes

Zoned Tooth is a tough and insubstantial fungus. The fact that the fruitbodies are long-lasting 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 2016.

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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