What You Should Know
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.
Other names: Zoned Hydnellum, Zoned Tooth Fungus, Zontaggsvamp (Swedish).
Hydnellum concrescens Mushroom Identification
Mycorrhizal with hardwoods (especially oaks); growing alone or gregariously; summer and fall; widely distributed in eastern North America.
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.
Running down the stem; covered with crowded spines that are 1-3 mm long; whitish at first, becoming brownish to brown.
2-4 cm long; .5-2 cm thick at apex; often swollen and velvety or spongy, especially towards the base.
Pinkish to brownish, often with zones of these shades; tough but pliant.
Odor and Taste
Odor not distinctive, or mealy; taste mild or mealy.
KOH on flesh blue-green to olive, then slowly gray to black--or promptly black.
Spores 4-7 µ; subglobose to irregular; prominently nodulose. Clamp connections absent.
Hydnellum concrescens Look-Alikes
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.
Tan colored without concentric zones; its spines are adnate to the stem rather than decurrent.
Hydnellum concrescens Medicinal Properties
Antitumor effects. Polysaccharides extracted from the mycelial culture of H. concrescens and administered intraperitoneally into white mice at a dosage of 300 mg/kg inhibited the growth of Sarcoma 180 and Ehrlich solid cancers by 100% and 90%, respectively (Ohtsuka et al., 1973).
Hydnellum concrescens Taxonomy and Etymology
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 1 - Author: GLJIVARSKO DRUSTVO NIS from Serbia (Creative Commons Attribution 2.0 Generic)
Photo 2 - Author: GLJIVARSKO DRUSTVO NIS from Serbia (Creative Commons Attribution 2.0 Generic)
Photo 3 - Author: Dominicus Johannes Bergsma (Creative Commons Attribution-Share Alike 4.0 International)
Photo 4 - Author: jacilluch (Creative Commons Attribution-Share Alike 2.0 Generic)
Shape: Tooth Fungi
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