Scaly tooth  (Sarcodon imbricatus)

Provisionally classified as Vulnerable in Great Britain (3). Digging up fungi without permission could also constitute theft under the Theft Act of 1968 (4).

The scaly tooth fungus is a member of the stipitate hydnoid fungi group. These fungi share some morphological characters, but are not a naturally related group (5). They are sometimes called 'tooth fungi', since they release their spores from tooth-like structures. The fruit body (the visible part of the fungus) is terrestrial and has a short stalk or 'stipe', hence the name 'stipitate' (6). The teeth are on the underside of the fruit body (6). Sarcodon imbricatus has been the subject of a taxonomic review (7) and it is now thought that most records from Britain may be of the closely related Sarcodon squamosus (8). Both species are fleshy, mushroom-shaped, and entirely brown, with the cap surface breaking up into large scales (5).

WARNING: many species of fungus are poisonous or contain chemicals that can cause sickness. Never pick and eat any species of fungus that you cannot positively recognise or are unsure about. Some species are deadly poisonous and can cause death within a few hours if swallowed.

Sarcodon imbricatus occurs throughout the northern temperate zone, in North America, Europe, and Asia (5). It is one of the most common stipitate hydnoids in Scotland (9), but is not known in Wales, and seems to be rare in England, where it occurs in Berkshire and Hampshire (10), with some records from Dorset and Breckland (6).

In Britain this species is associated with Scots pine (Pinus sylvestris) (8) and larch (Larix decidua) and occurs in pine wood habitats (6).

Fungi are neither plants nor animals but belong to their own kingdom. They are unable to produce their own food through the process of photosynthesis, as plants do; instead, they acquire nutrients from living or dead plants, animals, or other fungi, as animals do. In many larger fungi (lichens excepted) the only visible parts are the fruit bodies, which arise from a largely unseen network of threads called 'hyphae'. These hyphae permeate the fungus's food source, which may be soil, leaf litter, rotten wood, dung, and so on, depending on the species. With the exception of the earpick fungus Auriscalpium vulgare, all stipitate hydnoid fungi are ectomycorrhizal species; they form close symbiotic relationships with trees, and derive some of their nutrients from the tree's roots. Trees that have fungal partners have been shown to have a greater up-take of nutrients and trace elements as a result, so both the tree and the fungus benefit from living together in this way (11). Sarcodon imbricatus has been used as a dye and as food (6).

All species of stipitate hydnoid fungi are vulnerable to the effects of atmospheric pollution (6), soil eutrophication, soil disturbance (eg by timber management) and competition from vascular plants (6).

The UK Biodiversity Action Plan (UK BAP) has produced a Group Action Plan for 14 UK species of stipitate hydnoid fungi (3). The range of scaly tooth fungus does seem to have declined since 1960, but it may have been under-recorded (6). It is afforded general protection under the Wildlife and Countryside Act 1981, but it is not one of the four species of non-lichenized fungi given special protection under Schedule 8. Scottish Natural Heritage is conducting an extensive survey of tooth fungi in Scotland (9). Much more research on these fungi is needed if they are to be conserved (6); it is unfortunate that fungi are truly 'the forgotten kingdom' when it comes to conservation action (12).

For more on the conservation of rare fungi in the UK see Peter Marren's article available from Plant Talk On-line:
http://www.kak75.dial.pipex.com/Pages/26fungi.html

Information authenticated by Carl Borges of English Nature:
http://www.english-nature.org.uk/ and by Dr Peter Roberts of Royal Botanic Gardens, Kew:
http://www.rbgkew.org.uk/

• Ectomycorrhizal: an association between a fungus and plant roots, from which both species benefit. The fungal threads form a sheath around the root. The plant benefits as root uptake is increased as a result, and the fungus receives nutrients from the plant roots.
• Eutrophication: nutrient enrichment of aquatic or terrestrial ecosystems.
• Fruit body: in fungi, the fruit body is the visible part of the fungus which bears spores (microscopic particles involved in both dispersal and reproduction).
• Photosynthesis: metabolic process characteristic of plants in which carbon dioxide is broken down, using energy from sunlight absorbed by the green pigment chlorophyll. Organic compounds are made and oxygen is given off as a by-product.
• Spore: microscopic particles involved in both dispersal and reproduction. They comprise a single or group of unspecialised cells and do not contain an embryo, as do seeds.
• Symbiotic relationship: relationship in which two organisms form a close association, the term is now usually used only for associations that benefit both organisms (a mutualism).

1. National Biodiversity Network Species Dictionary (November 2001) http://www.nhm.ac.uk/nbn/nhm/index.html
2. Coutecuisse, R. (1999) Mushrooms of Britain and Europe. Harper Collins Publishers, London.
3. UK Biodiversity Action Plan, group Action Plan. (November 2001): http://www.ukbap.org.uk
4. English Nature (1998) The wild mushroom pickers code of conduct. English Nature, Peterborough.
5. Pegler, D.N., Roberts, P.J., & Spooner, B.M. (1997) British chanterelles and tooth fungi. Royal Botanic Gardens, Kew.
6. Marren, P. (2000) Stipitate hydnoid fungi in Britain. English Nature Research Report No. 420. English Nature, Peterborough.
7. Johannesson, H., Ryman, S., Lundmark, H., & Danell, E. (1999) Sarcodon imbricatus and S. squamosus - two confused species. Mycological Research103: 1447 - 1452
8. Marren, P. and Dickson, G. (2000) British Tooth Fungi and their Conservation. British Wildlife. 11, number 6 401-409.
9. Newton, A.C., Watling, R., Davy, L.M., Holden, E., & Ward, S.D. (2002) Progress towards implementing the BAP for stipitate hydnoid fungi in Scotland. Botanical Journal of Scotland54: 89 - 110.
10. Ewald, N. (2001) Survey of the New Forest for stipitate hydnoid fungi. Hampshire Wildlife Trust Report.
11. Emmet, E & Emmet, V. (2002) Fungi and Aspens: promoting biodiversity, aspen friends and foes. The biodiversity and management of aspen woodlands: proceedings of a one-day conference held in Kingussie, Scotland
12. Marren, P. (2001) Waxcaps and woodland mushrooms. Conservation of fungi in Britain and Northern Europe. Plant Talk On-line http://www.kak75.dial.pipex.com/Pages/26fungi.html