Hydnellum scrobiculatum

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***Hydnellum scrobiculatum***, commonly known as the **ridged tooth**, is a tooth fungus in the family Bankeraceae. Widely distributed in the Northern Hemisphere, it is found in Asia, Europe, and North America.

## Taxonomy

The fungus was first described as a species of *Hydnum* by Elias Magnus Fries in his 1815 work *Observationes mycologicae*. Petter Karsten transferred it to the genus *Hydnellum* in 1879. Canadian mycologist Kenneth A. Harrison published the variety *H. scrobiculatum* var. *zonatum* as a new combination in 1961, but this is now considered to be synonymous with *Hydnellum concrescens*. Common names given to the species include "pitted corky spine fungus", and the British Mycological Society recommended name "ridged tooth".

## Description

Fruitbodies of *Hydnellum scrobiculatum* have centrally depressed caps measuring Template:Convert in diameter. These caps can fuse together to form concrescent fruitbodies. The caps have wavy edges, and an initially felty surface that becomes scaly with age. Young fruit bodies are white, then pinkish-brown, then purplish brown, sometimes with white margins. Fruitbodies can become shiny in age.

The spines on the cap underside are up to 4 mm long. They are initially white, but become purplish brown in maturity. The spines are decurrent—they run down the length of the stipe. The stipe, which is roughly the same color as the cap, measures Template:Convert long by Template:Convert thick. Mycelium at the base of the stipe envelops and grows around forest litter. The flesh smells mealy (similar to freshly ground flour). The edibility of the fruitbody is unknown, but in general *Hydnellum* species are too acrid and woody to be palatable.

Like all *Hydnellum* species, *H. scrobiculatum* produces a brown spore print. Individual spores have a more or less spherical shape, with dimensions of 5.5–6.5 by 4–5.6 μm. They have wart-like projections (tubercles) on the surface. The basidia (spore-bearing cells) are narrowly club-shaped, four-spored, and measure 23–29 by 5–6.5 μm.

### Similar species

There are several species that *Hydnellum scrobiculatum* is often confused with—especially older specimens. These include *H. spongiosipes*, *H. ferrugineum*, and *H. concrescens*. The latter species is particularly similar to *H. scrobiculatum*, a fact that has been highlighted by conservation efforts in the UK.

## Habitat and distribution

*Hydnellum scrobiculatum* fruits singly, in clusters, or in fused groups in both coniferous and mixed forest. It is found in Asia, Europe, and North America. In the United Kingdom, it is considered vulnerable according to the biodiversity action plan for stiped hydnoid fungi, and endangered according to the Red Data List.

## References

1. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Fries 1815`
2. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Karsten 1879`
3. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Harrison 1961`
4. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `urlFungorum: Hydnellum scrobiculatum var. zonatum`
5. ↑ 5.0 5.1 5.2 5.3 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Pegler 1997`
6. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `BMS`
7. ↑ 7.0 7.1 7.2 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Ellis 1990`
8. ↑ 8.0 8.1 8.2 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Phillips 2013`
9. ↑ 9.0 9.1 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Huffman 2008`
10. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Arora 1986`
11. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Polèse 2002`
12. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Parfitt 2007`
13. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `Ainsworth 2010`
14. ↑ Cite error: Invalid `<ref>` tag; no text was provided for refs named `ENRR 2004`

## External links

* Template:IndexFungorum

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