Hydnellum concrescens

Description

Hydnellum concrescens is an inedible fungus. The spores are produced on spines on the underside of the cap, rather than gills. It has a funnel-shaped cap, typically between 2 and 7 cm (0.8–2.8 in) in diameter, which has characteristic concentric zones of color. The cap may also have radial ridges extending from the center to the margins. The spines are pink in young specimens, but turn brown with age.

This species is very similar in appearance to Hydnellum scrobiculatum, and traditionally, largely unreliable microscopic characteristics such as spore size and ornamentation have been used to distinguish between the two.

Common names: Zoned Hydnellum, Zoned Tooth Fungus, Zontaggsvamp (Swedish).

Mushroom Identification

1. Ecology

   Mycorrhizal with hardwoods (especially oaks); growing alone or gregariously; summer and fall; widely distributed in eastern North America.

2. Cap

   Often fused with other caps; 2-10 cm wide; planoconvex, becoming flat or shallowly depressed; finely velvety or nearly bald; not infrequently developing pits, radially arranged ridges, or elaborate outgrowths; brownish pink to pinkish-brown, sometimes fading to nearly whitish; with concentric zones of texture and/or color; the fresh margin bruising dark brown to black.

3. Undersurface

   Running down the stem; covered with crowded spines that are 1-3 mm long; whitish at first, becoming brownish to brown.

4. Stem

   2-4 cm long; .5-2 cm thick at apex; often swollen and velvety or spongy, especially towards the base.

5. Flesh

   Pinkish to brownish, often with zones of these shades; tough but pliant.

6. Odor and Taste

   Odor not distinctive, or mealy; taste mild or mealy.

7. Chemical Reactions

   KOH on flesh blue-green to olive, then slowly gray to black--or promptly black.

8. Spore Print

   Brown.

9. Microscopic Features

   Spores 4-7 µ; subglobose to irregular; prominently nodulose. Clamp connections absent.

Look-Alikes

1. Hydnellum scrobiculatum

   Very similar species. Officially, it is never zonate, develops a bumpy cap more frequently, and has spores whose nodules are rounded or flattened, and less prominent. It is usually recorded as growing under conifers. In the real world, however, collections are frequently made that seem to grab whatever features they want from the official concrescens and scrobiculatum lists, resisting the limits set by mycologists.

2. Hydnum rufescens

   Tan colored without concentric zones; its spines are adnate to the stem rather than decurrent.

Medicinal Properties

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.

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.

Photo sources:

Photo 1 - Author: GLJIVARSKO DRUSTVO NIS from Serbia (CC BY-SA 2.0)

Photo 2 - Author: GLJIVARSKO DRUSTVO NIS from Serbia (CC BY-SA 2.0)

Photo 3 - Author: Dominicus Johannes Bergsma (CC BY-SA 4.0)

Photo 4 - Author: jacilluch (CC BY-SA 2.0)