Fused tooth  (Phellodon confluens)

The fused tooth fungus belongs to the stipitate hydnoid fungi group. These fungi share some morphological characters, but are not naturally related (8). Stipitate hydnoid fungi are also known as 'tooth fungi', since the spores are released from tooth-like structures. The fruit bodies are terrestrial and have a short stalk or 'stipe', hence the name 'stipitate' (1). The teeth are on the underside of the fruit body (the part of the fungus that we see) (1). The flesh of all members of the genus Phellodon is tough and somewhat leathery; it becomes 'corky' when it dries (1) and develops a distinct spicy smell (4). The spores are spiny and white (4). The caps may fuse together to form one mass with a number of stipes, and may grow around and even engulf blades of grass and twigs. If they are growing on a slope, the fruit bodies can overlap to form layers of semi-fused caps (1). As specimens age the cap may change in terms of colour, shape and texture (1), but confusion can arise as the downy surface of the cap can darken greatly when it rains (4).

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.

Phellodon confluens is widespread in Europe and North America. It is widespread but rare in the south of England and Scotland (10), and there is a single record from Wales (9). It is known from the New Forest (11), but is one of the less common stipitate hydnoids at this important site (1).

This species occurs in broadleaved woodlands, but in Scotland it is also found in pine forests. It grows on sandy heathland, the sides of tracks, at the edges of marl-pits and on wood banks. It tends to be found in association with oak and sweet chestnut, and less frequently with silver birch, beech and pine (1).

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. This aids them in obtaining nutrients on poor quality soil, and means that are always found in association with trees (1).

Like Hydnellum, Phellodon species are often surprisingly free of invertebrate damage. It is thought that they may contain defensive chemicals that repel invertebrates and possibly even mammalian grazers (1).

There is no definite evidence that this species has actually suffered a decline (1), however it is rare and certainly needs attention (1). All species of stipitate hydnoid fungi are vulnerable to the effects of atmospheric pollution (1), soil eutrophication, soil disturbance (e.g. by timber management) and competition from vascular plants (1).

There are relatively very few records of Phellodon confluens, and it has probably been greatly under-recorded (1). The UK Biodiversity Action Plan (UK BAP) has produced a Group Action Plan for 14 UK species of stipitate hydnoid fungi (2). A number of sites that support this species, including the New Forest, are Sites of Special Scientific Interest (SSSIs) or reserves (2). Fused tooth fungus 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. Much more research on these fungi is needed if they are to be conserved (1); it is an unfortunate fact that fungi are truly 'the forgotten kingdom' when it comes to conservation action (7).

For more on rare fungi 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/